How to get rid of unwanted artefacts in OpenGL?

[sashen 0]

How does one get rid of the lines and overlapping textures where roofs and walls intersect?

[Jim Wilson 2,192]

This happens when you have two "coplanar" faces, or two faces that occupy exactly the same plane (or in this case, planes AND volume) in your model. This can be solved by lowering the wall heights and using peaks to match the bottom of that roof geometry, or by slicing the bottom of that roof geometry off such that it no longer occupies the same space as the wall.

OpenGL effectively doesn't know which face it should be showing, so it attempts to show both which results in this hatched look.

The lines are simply because you are in OpenGL with Draw Edges turned on, OpenGL is unable to combine surfaces like Hidden Line and some of the other render modes.

[Robert Anderson 61]

To take Jim's comment one step further. If this is a viewport presentation, use a stacked viewport. The "lower" viewport will be in OpenGL rendering with no edges, the "upper" viewport will be in HL. The texture artifacts at the gable walls can be fixed by reshaping the roof to be 0.01mm shorter.

[Andy Broomell 545]

On 11/14/2018 at 6:33 AM, Robert Anderson said:

To take Jim's comment one step further. If this is a viewport presentation, use a stacked viewport. The "lower" viewport will be in OpenGL rendering with no edges, the "upper" viewport will be in HL.

 

This could also be accomplished with one viewport by setting Background Render to OpenGL (and turning Edges off in Background Render Settings), and setting the Foreground Render to Hidden Line.

 

But on the Design Layer, you pretty much have to rectify the geometry or turn off Edges.

[Judy Cosgrove 4]

I love OpenGL!!!