KeyShot Forum

Technical discussions => Lighting => Topic started by: willchocks7 on August 16, 2016, 03:28:18 pm

Title: Keyshot can't render realistic shadows on cylinders?
Post by: willchocks7 on August 16, 2016, 03:28:18 pm
Hi,

I'm having some minor trouble with cylinders in my scenes. It seems that unless a cylinder is lighted from the direction of the camera, it always seems to render with a very sharp terminator line as one side of the cylinder falls into shadow. See the attached image for a better idea of what is happening.

I'm using just the 'basic' lighting setting with:

16 ray bounces.
0 indirect bounces
1 shadow quality
and 'self shadows' enabled

Has anyone else had this problem and how can I fix it?

Thanks
Title: Re: Keyshot can't render realistic shadows on cylinders?
Post by: guest84672 on August 16, 2016, 03:40:01 pm
This may depend on the tessellation of your model. Use the wireframe material and check.
Title: Re: Keyshot can't render realistic shadows on cylinders?
Post by: willchocks7 on August 16, 2016, 04:57:54 pm
Thanks for the reply

I put a wireframe material on and it seems to be fine. Very optimised but fine.

The kid's face also has the same problem happening on it with the sharp shadow edges.
I've tried changing the lighting to include more ray bounces and indirect bounces but still getting the same result :/
Title: Re: Keyshot can't render realistic shadows on cylinders?
Post by: DriesV on August 16, 2016, 10:36:01 pm
Are you using a Sun & Sky HDRI?
The sharp terminators can occur when using HDRIs with small, bright light sources (e.g. sun).
You shouldn't see this when using Interior Mode.

Dries
Title: Re: Keyshot can't render realistic shadows on cylinders?
Post by: bdesign on August 16, 2016, 10:57:59 pm
Ha! You beat me to the punch, Dries  ;)  I was just preparing a sample render with Interior Mode :)  Perhaps I'll upload it anyhow in a minute.

Eric
Title: Re: Keyshot can't render realistic shadows on cylinders?
Post by: bdesign on August 16, 2016, 11:11:27 pm
As Dries stated above, Sun&Sky and HDRIs with small, high-exposure light sources can cause this issue. You will most likely want to decrease the color values of your materials, and decrease the exposure, brightness, and saturation of your backplate when using Interior Mode, which I have done in my attached example render.

Eric