While using a section plane, weird things appear on a render. Some of them look like shadows of things behind and in front of the section plane, some like random rectangles. Ive had this issue for a while, but i cant figure out what causes it.
It happens in a specific model, and in the other one it doesnt. Its not a light problem, since i deleted every light source and cleaned up textures and it didnt help. I tried deleting models within the save but the issue is always there. I think it used to be only while using GPU, but now it is also with CPU.
I know its a strange problem but i am at my wits end.
You can try disabling “use object material” option from section settings in vray geometry..
If it is still the same, choose material “none”. It used to solve my problems..
It worked! I still dont know why it happened in the first place in some of the renders but i decide to not care, since now i have some sort of solution! Thank you so much 
What you said worked while rendering with CPU (because my drivers werent updated yet). The problem is that i fixed the GPU drivers, and now i have the same issue again (blocks on render). And i do need to use GPU, because CPU is 10 times slower than GPU.
Hello @monika_wolkowyska ,
Please note that such artifacts are usually caused by Section Planes (V-Ray Clipper). Please keep in mind the following limitations when using V-Ray Clipper (documentation link):>
- V-Ray Clipper works best with “closed” objects. The results on open objects (without a corresponding back face) are not well defined.
- Currently, the V-Ray Clipper may produce artifacts if there are overlapping triangles in the scene, regardless of whether they are part of the same object or not.
As every project is unique, there could be different reasons for these artifacts, but following these practices can help to avoid them.
What you could try is using the transparent material with Clipper. The exact steps are:
- Create new material and name it Clipper_opacity for example;
- Change its Opacity settings from 1 to 0;
- Assign this material to the Section Plane (first you need to disable Use Object Material):
Another workaround is to use V-Ray Camera Clipping to clip near objects instead of Section Plane. You can find an example in our documentation. Note that Camera Clipping is enabled for all cameras at once.