Wrong polygon z-value

[ErDetEnAnd?]

Hello.

I've constructed one 3DS as depicted below. If made transparent (like in the picture) I get the wrong polygon on top. The model consists of 4 walls and a floor (no planes).



Did I make something wrong in the 3DS, or is this a render issue?

[EgonOlsen]

It's a sorting/rendering issue. Transparent polygons have to be z-sorted to be rendered in the correct order. That ordering is done by the so called painter's algorithm, which doesn't ensure a perfect ordering. There's not much you can do about this. Splitting the object, i.e. separating the bottom from the rest and playing around with Object3D.setSortOffset(); may be an option if the object usually isn't visible from all sides.

[ErDetEnAnd?]

I see. What are valid values for the argument of Object3D.setSortOffset()?