<p>It appeared that it was exactly the problem explained in the link of my original post (<a href="https://computergraphics.stackexchange.com/questions/2192/cause-of-shadow-acne">Cause of shadow acne</a>).
The shadow function offset has been increased and the problem is solved!</p>

CC BY-SA 4.0
2021-04-21T09:37:28.503Z
2021-04-21T09:37:28.503Z
Balfar
<p>First of all I have to say that I am really new in the world of Computer Graphics. I apologise if some of my questions may appear trivial.
I am currently using a non-commercial ray tracing and physically based rendering software. I didn't have any problems with this until now : I have a scene where an .obj file representing a satellite is placed surrounded by a environment map light.
Here is an exemple of my problem appearing on the solar pannels :</p>
<p><a href="https://i.sstatic.net/KTHlk.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/KTHlk.png" alt="enter image description here" /></a></p>
<p>I have no idea where these strange forms could come from. I have to say that for this picture, the .obj file representating the solar pannel is a very simple parallelepiped. I also tried to suppress the other face of the object but nothing changed.</p>
<p>I saw this exchange (<a href="https://computergraphics.stackexchange.com/questions/2192/cause-of-shadow-acne">Cause of shadow acne</a>) that could maybe be related to my problem, but if someone has an idea of what could be the cause, I would be happy to hear it!</p>
<p>Thank you to all and have a nice day.</p>

<raytracing><shadow><artifacts>
What can be the cause of some strange ray shadows artefacts on a perfectly flat surface?
Balfar
# What can be the cause of some strange ray shadows artefacts on a perfectly flat surface?

(Asked by: username_0 on 2021-04-21)

First of all I have to say that I am really new in the world of Computer Graphics. I apologise if some of my questions may appear trivial.
I am currently using a non-commercial ray tracing and physically based rendering software. I didn't have any problems with this until now : I have a scene where an .obj file representing a satellite is placed surrounded by a environment map light.
Here is an exemple of my problem appearing on the solar pannels :

[![enter image description here](https://i.sstatic.net/KTHlk.png)](https://i.sstatic.net/KTHlk.png)

I have no idea where these strange forms could come from. I have to say that for this picture, the .obj file representating the solar pannel is a very simple parallelepiped. I also tried to suppress the other face of the object but nothing changed.

I saw this exchange ([Cause of shadow acne](https://computergraphics.stackexchange.com/questions/2192/cause-of-shadow-acne)) that could maybe be related to my problem, but if someone has an idea of what could be the cause, I would be happy to hear it!

Thank you to all and have a nice day.

**Tags:** raytracing, shadow, artifacts


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## 1 answers

### Answer by username_0 on 2021-04-21. Score: 1 | Accepted answer

It appeared that it was exactly the problem explained in the link of my original post ([Cause of shadow acne](https://computergraphics.stackexchange.com/questions/2192/cause-of-shadow-acne)).
The shadow function offset has been increased and the problem is solved!


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