slop-cad

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slop-cadThe slop is in the name.

Constraint-based parametric CAD that runs in a browser tab. The solver and the modelling kernel are compiled to WebAssembly, so the work happens on your machine and the file stays there.

Open the app
Read the guide
What it will not do

Say what must stay true

A dimension here is a rule the drawing has to obey, so you tell it that two lines are parallel, that a hole is 12 mm across, that an edge is 40 mm long. The solver moves the geometry until all of those hold together, and moves it again whenever you change one of them.

Sketch, extrude, blend

A closed profile pushes into a solid, and you can sketch on a face of that solid to add a boss or carve a pocket into it. Edges take rounds and chamfers. Finished parts leave as STL, OBJ or STEP.

Nothing leaves your machine

There is no account to make and nothing to upload. The solver and the kernel both run inside the tab, and saving writes a file to a disk you own. If the tab closes before you get to that, the browser has been holding the last document for you.

One number moves the part ​

A dimension here is a statement about the part rather than a label on a drawing, which is what makes it worth retyping. Change the 70 to 28 and the sketch re-solves, the solid is rebuilt from it, and anything standing on that solid moves along with it. The volume beside the timeline is recomputed in the same pass, so it stays the part's own measurement rather than a number you keep up to date by hand.

The reason to care about any of this is the second version of a part. When the plate has to be 55 mm rather than 40, the change is a number and a rebuild rather than an afternoon.

A part somebody else can size ​

This one builds a case for a 2.8 inch display board out of named numbers. The board is 86 by 50 mm, the wall thickness and the clearance around the board each have a name of their own, and the case outline is written board_w + 2 * (wall + fit) instead of 92. The pocket the board sits in and the window its panel looks through come off that same table, so no measurement in the model is typed twice.

Once the table exists, any row of it can be given a control: a slider with a range, a dropdown of the board sizes you build for, a heading to group them under. The last third of the clip is that panel doing the work. Wall thickness moves and the case thickens around a pocket that stays where the board needs it. The board width comes off the dropdown, its height is typed underneath, and the outline, the pocket and the surround of the window all re-derive from the pair.

Someone who has never opened the sketch can size the part this way, and the volume under the controls tells them what they would be printing.

What it will not do ​

The guide carries a long page on where this tool stops. These are the entries most likely to matter early:

  • Sheet metal, surfacing, simulation and drawings are absent rather than partial.
  • Assemblies go as far as holding one body against another. Nothing solves for a position that satisfies several requirements at once.
  • The exports are STL, OBJ and STEP. STEP is the one that carries the solid, so it is what to hand another CAD tool or a shop.
  • A photograph cannot become a sketch. Geometry arrives as DXF, Gerber, drill and board files, as a mesh, or as STEP.
  • Saving is something you do. Save writes the whole document to a file you keep; the browser holds the open document as a net under a closed tab, and holds exactly one.
  • A tablet works. A phone does not: below about ten inches there is no drawing area left worth placing anything in.

The full list goes further into each of them, and it is the page worth reading before you commit a project to this.

Open it ​

There is no installer, no account and no trial period. The application is a page, and opening the address is the whole of the setup.

If you would rather be walked through it, building a first part takes about fifteen minutes and ends with a solid you can export.

Open the app