@pilou said:

Inflate Components by Sdmitch ? Not sure that is you want exactly..
(Zip it and rename .zip in .rbz)

Thanks! I'll give it a try...

@d12dozr said:

Sounds like a job for JointPushPull!

Yep, tried this and it looks like it will do exactly what I need! Thanks!

Does anyone know of any extension that can do 3d object dilation/contraction?

When I say dilation/contraction, I mean reducing (or expanding) the volume of an object but not just resizing it.

For example, imagine a U-shaped object that you wanted to fit inside another same-sized U-shaped object. Resizing the first U-shaped object would not allow it to fit with a uniform gap inside the second U-shaped object. Similarly, if you resize a 20mm x 10mm rectangle by 50% and put it inside the original object you would end up with gaps between the smaller and larger object of 5mm at the left and right side and 2.5mm at the top and bottom.

So, is there a way to change the size of the object where the overall shell is, say, 5mm smaller? Off the top of my head, this would be a move of each plane by 5mm in the direction of a line perpendicular to the plane.

What I am trying to do is deal with tolerances for 3d printed objects so that they can fit within another. My 3d printer needs around 0.15mm gap between two objects that I need to fit within each other. Simple objects can be resized (and retain the same distance around the object but more complex shapes take a lot of time to manually adjust faces by 0.15mm.

I was thinking of writing an extension but I’ve never done that before so thought I’d ask first.