How can I find painting area (outer surface)?

How can I find painting area for complex shapes?

Find painting area.3dm (4.0 MB)

You can usually get the surface area of a polysurface (brep) like this:

Screenshot 2021-04-09 at 08.05.42

In your case, I’d first clean the geometry up though. You have non-manifold geometry, and what’s the deal with the hole in the middle that you patched up, but left bridging geometry inside?

Ideally, you’d want a nice, clean and tidy, watertight, closed polysurface to get an accurate area reading! (3.1 KB)

FWIW - That’s just the way it has to be - you need to weld those plates together and thus need access to the inner structures. When that’s done, you cover the hole.

At any rate…


@sajesh_pj - you should start from the model that has the individual plates. When you get that, you’ll have to clean that up as well because there are inaccuracies that, though they won’t stop production, they will get in the way of using Boolean Union in Rhino. When you get them in a state that they can be Booleaned, the result will be one outer polysurface and several inner polysurfaces. The area of the outer polysurface should then be the area that should be painted.

If you look at the model, it’s hard to tell if that’s the intention, or if it simply is a mistake in the 3d model. In reality, these triangular patches would be steel plates with a certain thickness, and not trimmed, flat surfaces. They also have duplicates at both sides!

Inside the cavity, there are small surfaces missing that should probably have been part of a chamfer that went wrong. The inside is also neatly designed. Why cover it up?
Structurally, plating these regions of the steel structures probably wouldn’t make much sense either. If you look at things like topologically optimized, cantilevering structures, they often have voids in exactly these regions.

Here is one sample file for individual plates. It is very difficult to clean up individual inside faces in rhino.
Find painting area-updated.3dm (4.1 MB)