Rendering troubles (usually with a GDL object/door/window)

[Anonymous]

I have been having some trouble with the glass in my renderings, if you look at the circled areas in the attached image there is a row of windows and doors where the color/reflection dramatically changes from one to the next. in this case it is a DWB door and a curtain wall object which are so different, this is not the first time I have run across this problem (it has happened in a number of models for me). Anyone have any ideas as to what might be causing this, and how to fix it. I typically render using the lightworks engine after setting my materials to match the internal engine.
Any tips would be appreciated.

sorry this probably should be in the rendering/presentation forum

[Laszlo Nagy]

I have experienced this behaviour before.
In that case, I tracked it down to the fact that in GDL, in certain Library Parts, the glass is created differently.
I don't know how well you know GDL, but I try to explain it in a way so it is easy to understand.

In one library part (probably in the one where the glass is of a lighter color) the glass may be created using the RECT command of GDL. This creates a rectangle with zero thickness.

In the other library part the glass may be created using PRISM command of GDL. This command creates a polygon shape with a thickness. In the case of a glass, this thickness may be something on the order of 1/8".

Because they are of different thicknesses, their transparency is different in renderings.

It can also be that the glass of both Windows is generated using the PRISM command but theit thickness is different, hence the difference in rendering.

The solution would be for you to track down does lines in GDL where the definition of the glass occurs and compare them to see if this is the case.