Overhang Analysis

Brad_Goodman

A tool, of particular use in 3D-printed designs to give you an analysis of the printability of a part (sans supports). i.e. WRT a starting (reference) plane and direction, it could show you:

1. Floating Overhang areas (like the tip in the middle of the letter "M" when it doesn't go all the way down)
2. Bridge areas (like the underside of a table)
3. Could let you color code the angle of a wall. (Most printers use 45-degrees from vertical as the max) - but some can do more (or less) - depending on the length of the overhang. So maybe show angle and even length of the angle/violation?

I'd see it as very similar to the draft analysis already present. 

lougallo

Have you tried using this FS?

Here is one we wrote for this type of analysis..

https://cad.onshape.com/documents/dc423b22d21926189296005e/v/13bb746b209f3c130a660c90/e/5a25a1cc508e032cd4f01af5

romeograham

Hold on @lougallo - what's the Sphere FS in that Document? 

lougallo

@romeograham We have an internal cube and sphere tool that we bake into our debugger for quick creation of objects for testing.

Brad_Goodman

@lougallo I can't see where it's giving me that visualization.

Jake_Rosenfeld

@Brad_Goodman

That feature creates a permanent edge on the model, but also the coloring of specific faces is only visible when then Feature Dialog for that feature is open (i.e. when that feature is being edited)

marshall_poland

I'd like to see this feature. I usually use the Draft Analysis as a quick check for overhangs that will be a problem for 3D printing; but it is not really meant for that and can be non-intuitive. I envision it working like this:

• User picks a "build plate" plane.
• User enters a max overhang angle (e.g. 45deg)
• The analysis is performed and the following surfaces are highlighted:
  1) Solid body surfaces which are overhung by more than the target angle (i.e. angle between build plate and surface is <45deg, and the surface's normal vector points away from the build plate rather than toward it).
  2) Surfaces which are "floating." Meaning there is no path from the surface to the build plate which stays on the body and does not go up, horizontal or down but at an angle <45deg to the build plate.
  

I imagine #2 would be the tricky part to implement. But 3D printing slicer software does this all the time.

Related: I've created a feature request to quickly create some of the drafts that are commonly used in 3D printed part design:

https://forum.onshape.com/discussion/19748/auto-draft-for-3d-printing-feature/p1?new=1