Glass puzzle

[steve.n]

Guys, I'm completely baffled, can you help?

Below shows 3 almost identical box models. The first was created in SolidWorks and the other 2 in 3DSMAX. All 3 have the same glass material applied and all have the same vray parameters. I've checked normals but that doesn't seem to make a difference. Any ideas why box 1 differs from the other 2? Thanks.



If it helps the 3dsmax2011 + Vray2.0 test file can be downloaded from here.

[super gnu]

id check if you have duplicate faces on the inside.. ive had many instances in the past when geometry has been imported with a 2-sided option enabled somewhere, which basically generates 2 copies of every face with the normals flipped. depending how thoroughly you checked the normals its possible to miss this.

[vlado]

It would also help if you can post the models here.

Best regards,
Vlado

[steve.n]

Thanks - I'll re-check those normals. The model is posted under the test image above. Ok, it seems it is a normals problem, thanks for your help.

[thablanch]

You do not have the same amount of faces on all of them.
Solid works model = 48 verts, and crooked faces. Max model = 8 verts and flat faces
I tend to turn off smoothing groups when doing flat glass, for better results, on imported stuff.

[Morne]

I can confirm that imported autocad models does the same for glass. Just go into poly edit mode, select all polygons, and clear smoothing groups. Then it will be fine.
or like thablanch says, just switch of smoothing on inport

[steve.n]

Thanks for your input guys - Flipping or unifying the face normal's solved the issue - Smoothing parameters did not seem to change anything from inside 3dsmax but I'll get the SW guy to see if it would make a difference on exporting.