general question about determining feature sizes of meshes

Coding Beginning Blender Code and Development
#1

I suspect I already know the answer to this but I thought I would ask.

When designing for 3D printing, there are a few unique things to keep in mind:

  1. overhangs: for several types of 3D printer, some stuff like “bridges” or features that jut out into space can’t be printed right. Since the model is built starting from a bottom layer and moving up, and using a moving extruder, things that hang downward, or straight out, can’t be printed right, without support layers.

  2. feature sizes: 3D printers have minimum resolutions that they can handle. They also have minimum cross-sections of features that they can produce.

I am wondering how hard it would be to write a script that checks for overhangs and feature sizes.

for #1 it would check whether any part of a mesh was considered an overhang.

for #2 it would have to check whether any part of the mesh had a cross section of less than X, where X is the minimum feature size of the printer.

I assume these things are hard to do, but are they REALLY hard to do, or just sort of hard to do?

What would be great is a tool that highlights or warns the user as they’re modeling, so they can avoid those problems before creating dependencies on invalid design features.

#2

at least one 3d printing company has an online tool which highlights critical areas of models, not sure how they do it. In Blender I would expect it to be very difficult in terms of the involved math. But maybe there’s a way to sort of run a physics simulation on your model. Overhangs would bend down and in comparison to the original vertex locations, you could tell how critical it is… But it’s just a crazy idea :wink: