What's the purple box associated with wedge-shaped prims?

[animats]

Simple wedge-shaped prim. The other basic prims don't do that.

Here we have a freshly rezzed wedge shaped prim. It's selected for Edit->Features, and the "eye" icon is off, so we're supposed to see the physics model in blue. But what shows instead is that undersized purple box.

The other prim shapes behave as expected. Here's the cylinder:

Collision model of cylinder. Looking good.

Cube and Sphere also looks fine. Torus has a mesh collision object, which makes sense.

What's special about wedge shaped prims?

(Asking because ray casts vs. wedge shaped prims may be doing something funny.)

Edited September 3, 2020 by animats

[Whirly Fizzle]

Are you using a viewer build without Havok?

[Lucia Nightfire]

Not seeing that with a tapered or cut box.

Must be a rando bug, else, file a bug report, heh.

[animats]

5 hours ago, Whirly Fizzle said:

Are you using a viewer build without Havok?

Oh, right. Yes. I'll look in a Havok viewer.

[Whirly Fizzle]

This post on Beq's blog explains what the purple outlines are: http://beqsother.blogspot.com/2017/10/blue-sky-thinking-physics-view-explained.html