OTOY Forums

Hi - I'm getting a strange occlusion or dark ghosting effect on a model I'm working on. If I place a torus, or any shape, close to the main tank model sphere it casts a strange shadow and a gradient down the sphere. See pic.

Things I've tried:

1) Increasing sample rate, switching from PT to PMC - in fact playing with all the kernel settings.

2) Alternative HDR environments from low to high resolution - 180 to 360 degrees.

4) Octane Daylight. This works, but it's not suitable for production. I need to use an HDR

Any other ideas? - I'm stumped!

Jason

It's occlued area by objects. Nothing is different than as in real world.

Maybe this image demonstrates my problem better. As you can see, the sun is casting a physically correct shadow onto the sphere but there's also a long gradient being cast on the tank
- this can't be correct surely? My modelling is to real world scale BTW

We can check if you put a sample scene. thx

Just a thought.. maybe your ray epsilon value is to calibrate a bit?

Here's a sample scene - a sphere with a torus around it. As you will see from the accompanying image the sphere is darker from midway downwards with the torus but renders normally without it.

My image is rendered with an HDRI but as you can see from the C4D file attached the same thing happens with Octane Daylight.

Thanks!c

It's an occlusion from ring object as i said before. You'll see difference if you play with ring. This is how that's in real world.

You're right! I rendered the same scene in VRay (should've thought of that before) and it's exactly the same.

Apologies for doubting you but it is a strange phenomenon.

Thanks!

jasonloader wrote:Apologies for doubting you but it is a strange phenomenon.
Thanks!

We're used to that. Enjoy it!

Sorry to return to this again - but now I've progressed the model a little further I'm doubting the gradient effect is naturally occurring again!. So I spent some time searching reference images and none of them demonstrate this effect at all. Here's my model side by side with one of the photos - sun in roughly the same place.

As I said, this happens in VRay too.

Has anyone experienced anything like this before?