Artefacts on Walls that contain Windows (cut holes)

[ronen_schmitz]

Hi everybody,
I am getting this artefacts on my walls (diagonal lines on the texture).

The walls contain windows that cut a whole into the walls, so I can easily move the window around for my client.
The wall material has a displacement map, that is shifted.
The window material also has displacement map, no shifting.

When I render only the building, this does not happen. But when I place the model into a bigger scenery with terrain, it happens.

Anybody have a solution to this, or a work around. Where am I going wrong?
Thanks

[kenancakir]

You should divide the surface, that way displacement works best.. Draw lines from corner of the opening to the edge of the walls..

[ronen_schmitz]

kenancakir Thank you!
Will try this.

[ronen_schmitz]

kenancakir Good morning to you!
I did some tests, but for now, it didn't solve the issue: If I divide the wall surface, the diagonal artefacts do get shifted inside the then smaller trunk of the divided surface.

Just to make sure my previous description of the setup well described. These wall surface don't actually have holes in their geometry. The holes are solely created by two window components from each side of the wall, that do cut the holes.
So there is no real "corner of the opening" to draw a line from...?
The building is placed as a skp file into a broader SKP scenery with a huge terrain. If I render the placed SKP file of the buildings, these artefacts do not appear. I wonder if this has something to do with huge terrain the SKP file is placed into?
Like SU always has issues with huge terrain or huge models.

[konstantin_chaos]

Hi ronen_schmitz,

Is it possible for you to share a simplified version of the model that we can use for testing?
The terrain size might actually be the issue. Not the complexity but the size itself.
But before I confirm I need to check the actual setup.

Thank you in advance,
Konstantin

[ronen_schmitz]

Hi Konstantin
Thanks for having a look. I simplified this as much as possible.
Here's the link to WeTransfer: https://we.tl/t-8NLlgvfLf4


This is on MacOS 11.6.1
SketchUp 2019 latest version
V-Ray 4/ Next

Thank you!
Ronen

[konstantin_chaos]

Hi ronen_schmitz,

Thank you very much for sharing the project.

The main reason for the artifacts seems to be the big distance between the world's origin and the hero building.
There is a floating point precision error that happens in V-Ray when the object in view as well as the camera rendering it are both very far away from the 0,0,0 coordinate.

There is unfortunately no straight forward way to fix this.
There are however a couple of things that might help you work around this:

• The artifacts should only be visible during Interactive rendering. V-Ray is able to correct such inaccuracies when Production rendering is started.
• The best possible manual workaround would be to select all objects in the set and move them in such a way that the house is positioned closer to the origin.

I'll additionally raise this question to the V-Ray Core development team and we'll hopefully find a way to improve this in the future.

Regards,
Konstantin

[ronen_schmitz]

Dear Konstantin,

thank you very much having a look into the problem and getting back to me.

If I remember well, the artefacts did appear in production rendering, but I will check again.
However, making sure the that the hero building is close to the 0,0,0 coordinate/ origin seems to be a very easy workaround.

I will try this, and post the results here.
Maybe keep this post open until then.

Thanks again very much,
Ronen