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CAD

CAD is where you model real parts: enclosures, brackets, mounts and anything else that has to fit something. You build a part from a list of steps, change any step later, and the part rebuilds. When it's right, export it for printing, for another CAD app, or for your scenes.

Getting in

CAD lives in Dev, beside websites, games and apps. Each part is a file in your project's cad/ folder, so it stays with the project.

  • CAD parts on Dev's front page lists the project's parts, newest first. Click one to open it, or the bin on its row to move it to the bin.
  • New CAD part asks for a name and opens an empty part.
  • Sample enclosure makes a part from a 90 by 60 by 30 mm box with 2 mm walls, four screw posts and a USB-C slot, to see how a part is put together.
  • Import brings in a .kitligcad file someone sent you.

The bar above an open part shows its name (click to rename it), its file, and whether it's saved. Parts save themselves a moment after each change. Dev on the left of the bar goes back to the front page.

Building a part

The toolbar is one row of menus. Each thing you pick adds a step to History, and the step's settings appear in Properties. All sizes are in millimetres.

Menu What's in it
Sketch New sketch on, Revolve, Sweep, Loft, and a plane to sketch on
Extrude A button of its own, as it's the one you reach for most
Solid Box, Cylinder, Cut, Hole and Text
Modify Fillet, Chamfer, Shell, Draft, Offset face, Pattern and Mirror
Enclosure Board, Enclosure round the boards, Split and Join halves
Insert Library and Decal
Export STEP, STL, 3MF and GLB, at the right

If the window is too narrow for the whole row, scroll it sideways.

  • New sketch on starts a drawing on a plane, on a side of the part, or on a face you click. See Sketching.
  • Extrude pulls the latest sketch into a solid. Type the height and press Enter. Use a negative height to go the other way, and set Does to Cut material in Properties to cut a pocket.
  • Revolve, Sweep and Loft make solids from sketches in other ways. See Revolve, sweep and loft.
  • Plane, offset from XY and Plane on a face… (click it), in Sketch, add a construction plane, a flat surface to sketch on. Offset it from any plane or side, and tilt it with Tilt (degrees).
  • Box and Cylinder add material.
  • Cut removes material with a shape you set.
  • Hole drills holes, with a counterbore or countersink if you want one. See Holes.
  • Fillet rounds edges.
  • Chamfer bevels edges.
  • Shell hollows the part out, leaving walls of the Thickness you set. Choose which side stays open, or None for a closed, hollow part.
  • Draft tilts the side walls by a few degrees, so a moulded or cast part comes out of its mould. Walls square to the Neutral plane tilt about where they meet it.
  • Split cuts the part in two at a plane. See Enclosures.
  • Offset face pushes a flat face out by the Distance you set, or pulls it in with a negative one.
  • Pattern repeats a step in a grid or round a centre. See Patterns.
  • Mirror copies the selected step across a plane, or the whole part when nothing that makes a solid is selected.
  • Text puts lettering on the part, raised or cut in. Set the words, the font, the size and the depth in Properties. Keep raised lettering at least 0.4 mm deep to print.
  • Board places a circuit board or other part to design around. See Boards.

Drag the view to orbit it, scroll to zoom in towards the pointer, and right-drag to pan. The line under the part shows its size, volume and weight.

Patterns

Pattern repeats the selected step, or the last one that made a solid, as a step of its own. Extrudes, holes, revolves, sweeps, lofts and text can all be repeated. Tick the steps it repeats under Repeats; each copy adds or cuts as its original does. Sits on sets the plane the copies spread across, and starts as the plane the original's sketch is on.

Choose a Layout:

  • Grid lays copies out Across and in Rows, with the spacing you set between one copy and the next. A negative spacing goes the other way.
  • Grid, every other row offset moves every second row along by Row offset, half the spacing to start with, for honeycomb vents and staggered holes.
  • Round a centre spaces Copies round Centre X and Centre Y. A full 360 degrees spaces them evenly; a smaller Angle (degrees) puts the last copy at the end of it.

Counts include the original. Change the original and every copy follows.

To copy curves inside a sketch instead, see Pattern in a sketch.

Holes

Hole starts with one hole through the middle of the top. If the last sketch has circles or points drawn on their own, it puts a hole at each instead. In Properties:

  • At is Points I type, on the plane in On, or the circles and points of a sketch. A sketch keeps holes where you drew them as the part changes.
  • Size fills in common screw sizes: clearance holes, holes for a screw to cut its own thread in plastic, heat-set inserts, and counterbored or countersunk screws.
  • Diameter, and All the way through or a Depth.
  • Head is Plain, Counterbore (a wider, shallow hole for a screw head) or Countersink (a cone for a flat head).
  • Goes sends the holes into the plane, or out the other way.

Note

The sizes suit most printers. Print a test plate with a few holes before a big part: printed holes come out a little small.

Revolve, sweep and loft

These start from the latest sketch:

  • Revolve turns the sketch's shapes about an axis: the sketch's X or Y axis, or a line you drew. Draw the axis as a construction line (X in a sketch), so it doesn't cut your shape in two. A shape can touch the axis but not cross it. Set Angle (degrees) below 360 to turn it part of the way.
  • Sweep pushes a profile along a path. The path is the lines and arcs joined end to end in its sketch. The profile is a circle, a rectangle, or the shapes in another sketch, whose origin goes on the start of the path. Use it for rails, handles and cable channels.
  • Loft makes a solid through two or more sketches in order, each on its own plane, such as a square base rising to a smaller square. It uses each sketch's biggest closed outline. Tick Straight sides between sketches for flat faces between them.

Parameters

Parameters are named numbers, like wall = 2, that any size can use. Open the Parameters tab beside Properties, press Add a parameter, name it and give it a value. A parameter can use the ones above it: outer = inner + 2 * wall.

Then type a name or a sum into any size field in Properties, such as wall, wall * 2 or outer - 1 in. The field turns blue and shows what it comes to. Change the parameter and every size that uses it changes with it. Sketch dimensions take them too, and so does the height you type after Extrude.

Sizes take +, -, *, /, ^ and brackets, the units mm, cm, m, in and deg, and min, max, abs, sqrt, round, floor, ceil, sin, cos and tan (in degrees). Rename a parameter and everything that uses it follows the new name.

Configurations

A configuration is a variant of the part: large and small, with and without vents, a lid or a tray. Under Configurations at the bottom of the Parameters tab, press New and name it. Then:

  • give any parameter another value in its box. Leave a box empty to keep the part's own value; type a number or a sum to change it in this configuration only.
  • tick the steps it leaves out under Steps left out. They show as off in History.

Showing picks the configuration you see, or The part as designed. Exports and layouts use the one showing. Steps you add go into the part itself, so every configuration has them unless it leaves them out.

Boards

Enclosure then Board places a model of a part you're designing around, shown in see-through green: a circuit board, a battery, a screen. It's never part of what you export, and if the part runs into it, its step in History says which body and by how much.

The boards built in are the WT32-ETH01, the red PN532 NFC board, the ESP32 DevKitC, the Raspberry Pi Pico, the Arduino Nano, a 0.96 inch OLED and an 18650 cell. Each is a few blocks for the board, its connectors and its headers, close enough to check a fit. Untick Pin headers on a board you've soldered straight to wires, and the headers come off it, so a case doesn't leave room for them. They also know their connectors (the Ethernet jack, the USB sockets, the OLED's screen) and their screw holes, which an Enclosure step uses. A box I size stands in for anything else, A STEP model… loads a maker's model of the real thing, and A KiCad board… reads your own board.

After those, the list offers every GLB, STL and STEP file in the project, marked Kitlig Asset. A GLB's metres and Y up are turned into millimetres and Z up for you. A STEP file is a solid like the built-in boards. A GLB or STL is a mesh: it shows and you can project from it, but it isn't checked for clashes.

Move a board with X, Y and Z, turn it with Turn (degrees), and tick Upside down for a board that hangs from a lid. The camera row's chip button hides the boards while you look at the part on its own.

Footprint sketch adds the board's outline seen from above as the next step, a sketch on XY. Give a clearance in millimetres, or 0 for the exact outline. A sketch step you select shows its shapes in the view, so you can see the outline before you extrude it. Footprints of whole layouts are covered in Dev.

Warning

Board sizes come from their makers' drawings. Clones differ, so measure yours.

Boards from KiCad

A KiCad board… reads a board file (.kicad_pcb, from KiCad 5 to 9). Kitlig takes:

  • the outline from the Edge.Cuts layer, with any cutouts inside it,
  • the mounting holes (footprints named MountingHole, and plain holes 2 mm across or more),
  • every footprint as a box the size of its courtyard, on top or underneath,
  • connectors at the board's edge (USB, Ethernet, barrel jacks, terminals and the like) as openings for a case. Pin headers along an edge don't count: nothing plugs in through the case there.

The message after it says what it found. The board's step shows its file, size and connectors, and Read again picks up a changed file.

Warning

A KiCad file holds no part heights, so Kitlig guesses them from the footprints' names: an RJ45 jack 13.5 mm, pin headers 8.5 mm, small resistors 0.8 mm. The guesses lean tall, which is the safe side for a case, but check the tall parts against the real board.

The enclosure step

Enclosure then Enclosure round the boards builds a box round the boards and models placed before it. Select its step to change it:

  • Fits round: which boards it fits. All of them, ticked, includes boards you add later.
  • One row per side (Left, Right, Front, Back, Floor, Roof): tick the wall on or off, and give it its own Thickness and Gap inside (the space between the contents and that wall).
  • Inside height: 0 fits the contents and the floor and roof gaps. Set a height for an open-topped tray or a sleeve.
  • Corner radius: rounds the upright corners outside. Inside corners follow, less the wall; under 1.5 mm they're left sharp.
  • Openings for connectors: an opening through each wall a board's connector faces, grown by Clearance.
  • Posts under screw holes: a post from the floor to each board's screw holes, Post diameter wide. Hold the board with picks how the board stays on it. Screw puts a Pilot hole down the post for a screw to cut its own thread. Post stands a thinner Inner post on top that goes up through the board's hole and 1 mm past it, so the board drops on and stays put with no screws. At 0 its diameter fits each hole, 0.2 mm under it; make it smaller if the board won't go on, or a touch bigger for a press fit. A hole with a part hanging below the board there gets no post, and the step says how many it left out.

The enclosure is hollow already, so there's no need to shell it. For a lid, add a plane, Split and Join halves after it, as below. A lid's joint needs walls all the way round where the halves meet: with a side wall off, or an opening across the seam, its step says so. Move the seam's plane up or down to clear the openings.

Layouts make all of this in one go: see Enclosures in Dev mode.

Decals

A decal is an image laid on the part, the way game engines put a sticker on a surface: projected along a plane's normal onto whatever faces it, flat or curved. It's its own textured piece, lifted a hair off the surface, and never part of the solid.

  1. Pick an image from Insert then Decal: the project's PNG, JPEG and WebP images, or An image file… to bring one in.
  2. Click the face it goes on. It's centred where you click, facing out of that face. (Faces must look along X, Y or Z; for others, set the plane by hand.)
  3. Press Height from the image's shape to keep its proportions.

Select its step to change it:

  • Place on a face picks a new spot with a click.
  • Sits on, Offset and From the other side set the plane it projects from. X, Y, Width, Height and Turn (degrees) place it on that plane.
  • Reach: how far in front of and behind the plane it looks for a surface. Give it more for a decal across a step or a curve.
  • Opacity.
  • Image in the decal: the UV editor. The outline is the decal; drag inside it to move the image, a corner to scale it (Shift for width and height apart), the round handle to turn it, with Ctrl to snap. Where the image no longer covers the decal, the part stays bare, so scaling it up shows just part of the image.

Decals show in the view (and the rendered view) and go into GLB, each as its own piece with its image. STEP, STL and 3MF leave them out.

Emboss

Emboss turns the image's ink into real shapes: Raise the ink stands it proud of the face by Depth, Engrave the ink cuts it in. Ink is decides what counts: The dark parts, The light parts (both against a Threshold from 0 to 1) or Anything not see-through. Holes in letters stay holes, and islands inside them stay too.

Embossed shapes are geometry, so they print and go into every export. The image is read at up to 512 pixels on its longest side, which is plenty for a logo; for fine lettering at a small size, Text draws cleaner outlines.

Note

A decal lies on the part as it is at the end of the history, so later steps don't need to know about it. Its emboss happens at its own step, like any other.

Looking at the part

The controls at the top right of the view change how you see the part, not the part itself:

  • Rendered, Shaded with edges, Shaded, Wireframe and See-through. Rendered shows each body in its material, lit like a product shot, with a soft shadow and no outlines or planes. See-through shows what's inside, such as latch arms inside a closed box, with every edge drawn.
  • The camera button saves the view as a PNG.
  • The cube button switches between perspective and orthographic. Orthographic has no perspective, so parallel edges stay parallel and sizes compare true across the view.
  • View turns to Front, Back, Left, Right, Top, Bottom or Iso, or fits the part to the view.
  • Keys, with the pointer over the view: V steps through the display styles (Shift+V goes back), 1 to 6 turn to Front, Back, Left, Right, Top and Bottom, 0 to Iso, F fits the part, and O switches perspective and orthographic. In a sketch only V works, as the camera faces the sketch and the letters are its tools.
  • Section cuts the view open, so you can see inside. Choose the direction, then drag the slider to set how deep the cut goes. The cut faces are filled in a different colour for each body, so you can tell the halves apart. The flip button keeps the other side.

Materials

The panel on the left sets what each body is made of (under History, when you show it as a list): PLA, PETG, ABS, resin, aluminium, steel, brass, wood and more. A material brings its own colour and finish in the Rendered view and in GLB files; click the colour swatch to change the colour. Each body shows its weight, worked out from its volume and the material's density.

The palette button opens the material itself: lit, unlit or toon, colour, metalness, roughness, Clear coat for gloss plastics and paint, See-through for clear parts, and Density for the weight. These are the same materials Kitlig's games use, so a part keeps its look when it goes into a scene. Picking another material from the list replaces your edits.

Note

The weight is for a solid part. A 3D print with infill weighs less.

Sketching

A sketch is a flat drawing that turns into a solid. Pick a plane from Sketch then New sketch on and the view turns to face it. A sketch on a side of the part moves with that side if the part changes size.

To sketch on a particular face, pick A face… (click it) at the end of the list and click the face: any flat face, at any angle, a slope from a chamfer included. The sketch sits on that face, with its X running level. Kitlig finds the face again every time the part rebuilds (the flat face looking the same way, nearest where you clicked), so the sketch follows it when the part changes. Planes work the same way with Sketch then Plane on a face… (click it), and every Sits on list ends with A face… (click it) to pick again. Press Finish sketch (or Ctrl+Enter) when you're done, and double-click a sketch in History to go back into it. The part shows as it stood at that step.

Scroll to zoom and right-drag to pan. F fits the view to the drawing. When you type a size, the view stays where you put it; it only moves if what you just changed would end up off screen, and then it pans to it rather than zooming out to the whole drawing.

The display style and Section sit beside Finish sketch, so you can see through the part or cut it open while you draw on it. V steps through the display styles here too.

Drawing and typing sizes

Pick a tool, click to start, and a box appears on the shape. It already has the keyboard, so just type the size. Tab moves to the next box, and Enter places the shape. While a box is empty the shape follows the pointer, and the numbers bottom left show where you are.

Tool Key Boxes
Point . None. Each click puts down a point on its own, for a hole centre or something to dimension from.
Line L Length, Angle. Lines keep going from the last end until you press Esc.
Rectangle R Width, Height
Centre rectangle Shift+R Width, Height, measured across the whole shape
Circle C Diameter
Arc A Radius. Click the centre, type the radius, then click where it ends.

A size you type stays with the shape as a dimension. You can type sums and units: 10+2.5, 90/2, 1/2 in, 2.5cm. A number on its own is millimetres, or degrees in an Angle box.

Lines close to level or upright snap to it and stay that way. Clicking near an existing point joins to it, and a circle shows where it will join. Near the middle of a line, a triangle shows instead: what you click there stays at that line's middle, even when the line changes length later. Pointer positions snap to the grid, which gets finer as you zoom in.

Hold Ctrl to turn all of this off and put the point exactly where the pointer is: no joining, no middles, no grid and no level or upright lines. It works while dragging a point with the Select tool too.

Press X for construction lines, which guide a drawing but don't become part of the solid. With curves selected, X flips them instead.

Dimensions

Press D and click what you want to measure:

  • A line for its length, a circle for its diameter, an arc for its radius.
  • Two points for the distance between them. Beside the box you can switch between a straight, horizontal or vertical distance.
  • Two lines for the angle between them.

Type the size and press Enter. Double-click any number to change it, and the drawing follows. Clicking something that already has that dimension opens it.

Constraints

Constraints hold a drawing together. Select curves with the Select tool, holding Shift for more than one, and a button lights up if it fits your selection: Horizontal, Vertical, Parallel, Perpendicular, Equal, Tangent, Concentric, Midpoint and Coincident.

Each one leaves a small badge. Click a badge or a number and press Del to remove it. Drag a point to see what's still free to move. The readout shows how many ways the drawing can still move, and says Fully constrained when it can't, at which point the lines turn blue.

If a constraint or size can't be true with the rest of the drawing, Kitlig says so and leaves the drawing as it was.

Project

Project brings the part into your sketch, so you can draw from what's already there. Press P and the part's edges appear in purple, flattened onto the sketch. Boards placed earlier in the history come too, meshes included, so you can draw straight off a model you didn't make in CAD. Choose what to take:

  • Points: a corner or the centre of a curve.
  • Edges: one edge.
  • Faces: the whole outline of a face, holes included. Where faces overlap, you get the one nearest you.

Click to bring it in. Projected lines are fixed in place, and you can dimension and constrain to them. They also extrude like any other lines. To use one as a guide only, turn on construction with X first.

A circle facing you arrives as a circle. A curve seen at an angle arrives as short straight lines.

Projected lines follow the part. Change a size earlier in the history, or move a board, and they move with it, along with anything you've drawn from them: dimensions, constraints and offsets all come along.

Note

Kitlig finds each projected item again by what kind of edge it was, which way it ran and where it sat on the part. That works well for changes in size. If the edge is really gone, the sketch shows a warning and the line stays where it was. If an edge has been replaced by something quite different, Kitlig can pick the wrong one, so check the result after a big change.

Only what you projected follows: if a change adds a new edge to a face, that edge doesn't join in by itself. Project it too.

If the part changes in a way the sketch's constraints can't follow, the sketch stays as it was and shows a warning.

Offset

Offset makes a copy of a shape a set distance away. Press O and click a curve: the whole chain joined to it is picked, with its corners rejoined in the copy. Move the pointer to the side you want, type the distance and press Enter.

The copy stays tied to the original. Change the original, or double-click the distance, and it follows. To cut a pocket inside a face: project the face, offset it inwards, then extrude with only the middle shape chosen, as a cut.

Pattern in a sketch

Select curves, then press G or the pattern button in the sketch toolbar. Choose a layout, the same ones as the Pattern step, and the copies show as you change the numbers. Press Make copies to keep them.

Each copy gets its own points and keeps the constraints among the curves you copied, so a copied square stays square. A copy's diameter or radius follows the original's: change the original's and they all change. Copies turned round a centre drop their horizontal and vertical constraints, which wouldn't hold any more.

Trim and round corners

Press T for Trim, then click the piece of a curve you want gone: it's cut away back to the curves crossing it. A curve nothing crosses goes altogether, and a circle crossed twice becomes an arc.

Press Shift+F to round a corner. Type the radius in the box that appears, then click the corner where two lines meet. The lines are shortened to meet an arc that's tangent to both, with a radius dimension you can change later.

What extrudes

Curves divide a sketch into shapes, wherever they cross or touch. A line across a rectangle makes two shapes, and a circle inside it makes a ring and a disc. Construction lines never count: they don't divide anything, and a shape drawn only in construction isn't a shape.

Extrude starts with all of them, apart from shapes inside another, which stay holes. Select the extrude in History and its shapes appear on the part, in yellow when they're in use. Click one to turn it on or off, or use the list under Shapes in Properties. All takes every shape, holes included, and Reset goes back to the start.

Your choices stay with the shapes as they change size. A shape you add to the sketch later joins in by itself, unless it's a hole.

Measuring

Click the ruler in the toolbar, then click two points on the part. Clicks near a corner land exactly on it. The distance shows on the line, and the top right shows it along each axis. Click again to start over.

Changing a step

History runs along the bottom of the view as a strip: one button per step, in the order the part is built, with the selected step's name showing. Hover a step for its name. A red dot marks a step that failed and an amber dot one with a warning; select it and the reason shows above the strip.

Click any step and change its values in Properties. The part rebuilds when you leave the field. In the strip:

  • The yellow bar is the roll marker. Drag it back to see the part as it stood at an earlier step, or click between two steps to move it there. On a long history, hold it near either end of the strip and the strip scrolls that way. The steps after it fade out, and new steps go in at the marker. The arrows at the left step it back and forward one step at a time, or jump to the start and the end.
  • Drag a step to another place in the strip to change the order. A blue line shows where it lands.
  • Double-click a sketch to draw in it again.
  • Right-click a step for Roll back to here, Roll back to before this, Turn off (it leaves a step out without deleting it), Move earlier, Move later and Delete.

Prefer the list? The list button at the right of the strip puts History back on the left as a list, with the same controls when you hover a step: Roll back to here, Turn off, Move up, Move down and Delete. The strip button at the top of the list brings the strip back. Kitlig remembers which you chose.

Ctrl+Z and Ctrl+Shift+Z undo and redo while the pointer is over CAD.

Choosing edges

The quickest way is to click them. Set Edges to Edges I click, or press Pick on the part, and every edge of the part shows. The part shows as it was just before this step. Click edges to add them, click again to take them off, and press Done.

Kitlig remembers each edge by what it was and where it sat on the part, so a picked edge is found again after you change a size. If one is really gone, the step says so and leaves it out.

Note

Some pairs can't be rounded together even when each works alone, such as the outside and inside edges of a thin wall. If a fillet fails, try a smaller radius or fewer edges.

You can also describe edges rather than click them, which suits rules like "every upright corner":

  • Edges on a side: the top, bottom, left, right, front or back of the part. These follow the part, so a fillet on the top stays on the top when you make the part taller.
  • Edges on a plane: edges at a fixed distance along a plane. These stay at that distance if the part changes.
  • Edges along an axis: every edge running in the direction you choose. Z picks the upright corners of a box.
  • Every edge does what it says.

Shell's Open side and Offset face's Face work the same way, and can also be a plane, such as the one a split uses.

Enclosures

To make a box in two halves:

  1. Make the solid outside shape, rounded and chamfered how you want it.
  2. Press Split. It adds a plane across the middle and cuts the part at it. Move the plane with its Offset to choose where the halves meet.
  3. Press Shell. After a split it opens at the split plane, so both halves come out hollow and open at the seam.
  4. Add what holds them together from Enclosure then Join halves.

Each half is a Body, listed on the left with its material and weight. Hide one to look inside the other. Exports take only the bodies you can see, so hide the lid to export the base on its own. GLB keeps the bodies as separate pieces.

Joining the halves

Choice What you get
Screw posts A post in each half. One gets a hole the screw cuts its own thread into, or one sized for a heat-set insert; the other gets a clearance hole and a counterbore for the head. Sizes M2 to M4.
Alignment pins Pins standing up from one half into sockets in the other, with the Clearance you set.
Lip and groove A lip along the inside of the walls on one half, fitting a groove in the other. It keeps the halves lined up and closes the seam.
Snap latches A springy arm with a ramped hook on one half, and a window in the other's wall that the hook clicks into. Add one per side with Add a latch.

Screw posts and pins go at the inside corners on their own, and follow the box when it changes size. Place by hand turns those into places you can edit, measured across the split plane.

The screw heads, the sockets, the groove and the latch windows go on the side the split plane faces. The plane Split makes faces down, so screws go in from under the base. Each one has a setting to put them On the other side instead: Screw heads, Sockets, Groove or Windows. Places you set by hand stay where they are when you flip.

Note

These need walls to work on: shell the part first. Lip and groove checks there's enough wall left outside the groove, and latches refuse a hook deeper than the wall. Clearances suit most printers; check yours with a test print before a big one.

When a step fails

A step that can't be done turns red and says why, and everything after it fades out. You see the part as it was before that step, and nothing's lost: fix the step and the rest come back.

A common one is a shell on rounded corners. A corner's radius has to be bigger than the wall thickness, or there's no room for the inside of the corner.

Printing

The Print tab beside Parameters holds the printer the part is made on, and checks the part against it whenever it changes.

Printer starts from a preset: FDM with a 0.4 or 0.6 mm nozzle, FDM on a small (180 mm) bed, resin, or SLS nylon from a print service. Change any number to suit yours.

The checks:

  • Fits the bed: as it stands, or turned onto another side, or not at all.
  • Overhangs: faces that lean out more than the Overhang limit from upright, which need support. When a body has none upside down (a lid usually doesn't), the check says to print it that way.
  • Walls: places thinner than the Thinnest wall the printer can make, measured straight through from a sample of faces.
  • Weight: the solid weight from each body's material, the volume, and the length of filament. With infill a print takes less.

Mark on the part shows overhangs in red and thin walls in orange.

Fits and holes

Clearance is the gap the printer needs between parts that fit together. Use it for every fit in the part sets it on every pin, lip and latch between halves, and (at 0.3 mm or more) on enclosures' connector openings, as one change you can undo.

Holes print a little small. With Make round holes bigger by it ticked, hole steps and round cuts are made bigger by the Hole allowance; you still type the size you want. A part with no printer chosen builds exactly as drawn, so parts made before printers existed don't change until you pick one.

Note

The checks look at the part as it stands, Z up, each body on the bed by its lowest point. They don't slice it, so they can't see bridges or how a slicer will support a part; treat them as a first look.

Parts library

Insert then Library has ready-made features for enclosures. Pick one, then click the face it goes on (a face looking along X, Y or Z):

  • Openings: USB-C, micro USB, USB-A, Ethernet (RJ45), a DC barrel jack, an SD card slot, a 12 mm push button, a 6 mm toggle switch, 5 mm and 3 mm LEDs, and PG7 and PG9 cable glands. They cut 6 mm in from the face, through any sensible wall.
  • Vents: six slots, or a honeycomb of 3 mm holes.
  • Mounting: four recesses for stick-on rubber feet at the corners of the face you click, a wall-mount keyhole, and an M3 screw standoff (click the floor inside).

Each is ordinary steps (extrudes, with a pattern for the repeated ones), so you can move, resize or delete it in History.

Saving and exporting

Parts save themselves. The save button in the toolbar saves a copy as a .kitligcad file, to send to someone else. Export from the Export menu on the right:

  • STEP is for other CAD apps and for manufacturers. It keeps exact curves.
  • STL is for 3D printing.
  • 3MF is for 3D printing too, and keeps each body as its own object with its colour, so a slicer can print the halves of a box in different filaments.
  • GLB is for your scenes and for Kitlig. It arrives the right way up, at its real size in metres.

The page button next to the ruler makes a Drawing: front, top and right views in third-angle projection with hidden edges dashed, an iso view, the overall sizes and a title block. Save PDF prints it to scale on A4 (or A3 for a big part); Save SVG is for editing it, or for a laser cutter.

Kitlig reads every STEP file back before saving it, and won't save one that doesn't match your part.

Warning

A Shell placed after a Fillet can't be written to STEP. The step shows a warning and STEP export stops until you fix it. Move the shell above the fillet with Move up. STL and GLB still work.

Building parts with an agent

An agent connected to Kitlig's MCP server can build a part for you, step by step. It reads how parts work, adds and changes steps, sets parameters and materials, looks at the part through screenshots, and saves STEP, STL, 3MF, GLB and drawings. Everything it does lands in History as steps you can change, and as undo steps.

The tools are cad_reference, cad_get_part, cad_set_part, cad_add_step, cad_update_step, cad_remove_step, cad_set_parameters, cad_set_material, cad_export, cad_drawing and cad_screenshot. Each change answers with the rebuilt part, including any step that failed and why, so the agent can fix its own mistakes.

Note

The part lives in Kitlig's window, so keep Kitlig open while an agent works on it.