Mesh Physics Query

[Carbon Philter]

I thought I had got the hang of mesh physics shapes but seem to have misunderstood and would appreciate some assistance in explaining it.

I created a handrail for an arch type stair/walkway using 5 and 3 face cylinders to form the rails and a simple box derived physics shape. Everything uploaded fine and I set the physics to prim assuming that the bounding box would follow the shape I created from the physics dae file. I find however that even though the physics shape displays as following the handrail shape I cannot pass under the arch section of the handrail and it behaves just as the lower edge of the convex hull shape.

Can anyone advise whether that is correct or might I have done something incorrectly?

Thanks.

The pics are of the handrail, and the physics shapes of both prim and conves hull settings.

[Casper Priestman]

I find this happens on the physics tab of the upload menu when I use simplify. If I just however select the shape from file and "analyze", everything works as it should, but simplify always gives me results like the one you're showing.

[Carbon Philter]

Thx Casper - that worked!

Tried Analyze then Simplify and it was as before but just selecting Analyze changed it, though it added 2L$ to the upload cost while LI abd Physics costs were the same as before.

I confess I'd never paid any attention to the Analyze/Simplify part of the Upload process. Guess I need to remember to do that every time.

[Lillith Anatine]

I tried this using those same steps with a mesh that was nothing but a floor with walls extruded straight up, no ceiling.

 

I used the same .dae model as the physics shape and used analyze, I chose "high" without re-picking the model from the file, etc., all without using "simplify."

 

I can't walk into my room. I seriously dont understand this. Upload fees get expensive.

 

 

[Drongle McMahon]

1. Did you set physics shape type to "Prim"? That is necessary to use the decomposed physics shape. Otherwise (default type = "Convex hull") it will use the default convex hull for the whole mesh. This applies to both triangle-based and decomposed physics shapes.

2. Do your walls have both sides? If not, thje decomposition can fill in the internal space. (You might be able to prevent this if you makr vthe normals point inwards.)

3. For simple buildings, the triangle-based physics weight (don't click "Analyze") is often lower than that of the decompsed shape, because it is only a few large triangles.

4. If you use a decomposed ("Analyze") physics shape, it is safest to supply it as a separate mesh consisting only of non-overlapping convex shapes; in this case the appropriate set of boxes, one for each wall (more if there's a door and/or windows) and the floor.