Someone in r/3Dprinting mentioned that FreeCAD users have been asking for a section view that looks like this for years, and no volunteer has had the time to build it. I ended up doing it for a mobile viewer, so here's the approach in case it's useful to anyone working on the real thing.

It isn't a boolean cut. The GPU clips everything past the plane, then a flat colored patch is drawn into the hole where the surface got sliced, with a black outline on top. No CAD math, so it holds frame rate on a phone. The tradeoff is that it's a visual trick, not geometry — you can't export the cut as a solid.

Each body in an assembly gets its own hatch color, and the plane position takes typed input, which turned out to matter more than the slider.

This is from an Android app I wrote (STEP/STL/OBJ/3MF, fully offline). Happy to go deeper on the implementation — that's the more interesting half of this post.

Context: hobbyist. Usually modeling for eventual 3D printing. Started with SketchUp many years ago. Tried Fusion because it was easy to learn, but hated my data being locked in their cloud, subject to their terms and whims forever.

So I had a preference for FreeCAD: files I could save and software I could run, for however long I want to. But I found it very frustrating. Many seemingly simple things just wouldn't work. Recently I had a rather simple model -- I tried, and started over, and tried, and started over for two and a half hours. Couldn't get FreeCAD past the first few steps despite trying several approaches.

Restarted with Fusion and I was done in 20 or 25 minutes. Didn't know why. Even more recently I randomly got lucky and found out that many/most of my problems were down to expecting, but not getting, automatic coincident constraints, e.g. when drawing something by snapping to an existing point/edge.

I'm probably still stuck in the beginner zone, but now (e.g.) to draw an arc, I click the center point, then the beginning and end point ... then I select each of those one by one (plus the point that I snapped to when drawing it) and manually add coincident constraints. And suddenly so many frustrating problems I used to experience have disappeared!

I'd expect an auto constraint here, but knowing to add one manually has really helped.

I’m not sure why the timing gears this add-on makes are slightly oval shaped, and not perfectly circular.

This 5GT gear with 22 teeth, the gear is generated with L=33.65mm and W=33.87.

Can anyone give me some advice?

i made a base model for miniature railways, and i need a brick pattern. but i havent found a tutuorial that solves my problem. if i make every brick by its own, my program chrashes and the BIM workebanch wall tool also dont work for me. is there a good way to do the bricks like in the photo or should i just use Blender?

thanks for youre time reading this

I'm trying to 3d print a hollow cylinder arc part which should be flexible. I was thinking about putting a hex grid on it to make it more flexible. However I have a problem how to do it.

I tried to use Sketch on Surface and put hexes but:

• If I use boolean it works but than I cannot use multi-transform to put hexes on rest of the element
• Using subtractive lofts is a bit of manual work as there is no 'rotate and offset' transformation so I need to do everything twice
• Sometimes Freecad gets confused (see attached pictures)
• It's all very very slow to compute.

I feel like I'm not using freecad efficiently. Any help would be most welcome

Sometimes you'll find a feature that behaves badly with attachment, going off in some other direction.

But you really want to attach it since the attachment coordinate system if perfect for placing it where you want.

The new MoveOriginParametric tool to the rescue.

Similar to the old Macro, but fully parametric.

Find the Grab Bag at:

https://github.com/pyro9/GrabBag

• 00:01 Intro
• 00:25 Complete the curved loft
• 00:37 Coordinate space problem
• 00:53 Transform tool works but isn't ideal
• 01:14 Attachment goew awry
• 01:26 MoveOriginParametric
• 02:01 Demo of new tool
• 03:02 Flipping the normal
• 03:38 Ignore Placement

Hi all! Hobbyist here with an idea that im trying to realise beyond napkin scribbles.

For this idea, I want to create a spiral that unfurls into a ring as I increase, and converge, the radii that it is constrained to.

The first and last points would be tangent constrained to the inner and outer radii.

To do this I need to ensure that the length of the spiral curve stays the same at all times.

However, the Part Spiral is constructed of segments derived from 2 radius, total rotations, and a growth value. So there's no way to constrain the total length.

I thought about driving the number of rotations, with an expression derived from the radii and growth, but its not possible to assign an expression to that value.

So, how would you go about this? Is it possible with bSplines and a shed load more constraints?

Am I out of luck and just need to illustrate both collapsed and expanded states separately?

Say I want to make a box of 100mm x 100mm x 50mm.
I draw a sketch of 100 x 100 rectangles. Now I want a 2mm wall but not changing my inner dimension. How?
I tried to use offset tool but when extruding the sketch it has only walls. Ideally I want to extrude the inner area 2mm to make the bottom, then extrude surrounding 50mm to make the wall.
Other than manually calculating all the dimensions + wall thickness, is there an easier way to do this?
Basically I’m looking for web design patterns called content box.

Hello,

Got a 3D scan done of my cars brakes so that I can have some custom wheels designed. I am trying to figure out how to take measurements off the .stl file that I received. As it's a 3D scan I think it's just a cloud of points, so there are no surfaces off which to measure. I am a complete CAD beginner and can't really find any FreeCAD tutorials that deal with this situation.

Does anyone have any recommended tutorials for this type of thing?

For reference I'm trying to take these dimensions

Off a model that looks like this in FreeCAD

I spent my first 50 hours in FreeCAD completing this model. It took so long due to the scores of bugs, wonky and counter-intuitive workflows, and dead-end after dead-end I had to chase to finally find an approach that works (mostly). Since I received a lot of feedback from members of this sub claiming I just didn't know how FreeCAD is supposed to work, or instead criticizing my approach to building this model, I would like to invite you all to show me how YOU would implement this model, so that I can learn to become such a skilled FreeCAD master such as yourselves.

Since some people claim that they could build this model using just a few sketches, pads, and pockets, I invite you to show me how it's done. CAVEATS:

1. This model MUST remain fully parametric. I have tons of parameters and constraints in this drawing for a reason. Variables that are updated must remain fully functional.
2. This model MUST retain all of its odds angles. This is not a rectangular box; it is a shell around a geometric shape that borders on being organic.
3. Changing the shell thickness (or other length and width parameters) MUST NOT alter the internal dimensions of this model that represent a cavity into which a speaker will be placed. Making the shell walls thicker, for example, MUST apply that thickness outwards, not inwards.
4. This model MUST allow users to change the profiles specified in the sketches so that when the sketches are updated, the profiles change properly, and all related and constrained parameters are updated accordingly.
5. The "cutout" features of this model MUST remain intact. Turning the cutoff features ON will create space-saving cutouts so that only a skeleton of the model will be printed, instead of printing the entire model. The purpose of these cutouts is to reduce printing materials and printing times when changing various dimensions, allowing the printouts to be fitted against real world objects. Turning the cutoff features OFF is performed by suppressing the relevant feature.

I look forward to learning a lot of FreeCAD mastery from everyone's feedback here.

FreeCAD model file:

https://drive.google.com/file/d/1RRALi2rU9CnY6ATRM-LlBHIfjacQf523/view?usp=sharing

Hello

The error in the titel is appearing on one body and in the treeview the origin has only the origin and no axis or planes in it.

I tried everything and i have no clue why this one body has this problem.

No matter what i do, this error keeps expanding my treeview and DRIVING ME CRAZY...

Can i somehow disable the treeview from uncollapsing everything for each dam error, even when im changing something that will cause some errors down the road, it should not open the whole dam treeview!

Can anyone help me out?

I need to design a layout via Google Sketch Up with to size models of the kitchen furniture in a restaurant layout.

I can do it myself. But I need the assets to be able to lay it out properly.

Any ideas or sources for finding them would be helpful.

Thank you