BIMx Global Illumination on Pool - Black Surface

[Anonymous]

Hi everyone,

I'm having a strange bug with global illumination in a model I'm working on. When I render GI, a transparent pool water surface has an inconsistent hue. In some areas, it appears black and desaturated. The areas generally correspond to more shallow parts of the pool but not consistently:

The strangest thing about this bug is that I was not having this bug in a previous save of the model from a few weeks ago. When I export a BIMx from the old model and render GI, the pool looks exactly how it should. When I export a BIMx from the new model and render GI, I get the bug.

I compared models and tried isolating any differences that might be contributing to the problem. I've tried all of these things, but the bug remains:

- The old model used a morph instead of a slab for the pool surface. I tried changing the new model to a morph, but no success.
- Old model had a 'missing' building material with a surface override. Imitated those settings on the new model's slab, but no success.
- Wondered if perhaps a layer change had contributed to the bug - no success
- misc. other similar logic / tweaks did not help.

It's strange that, besides what I listed above, all things are essentially equal between the two models, yet the pool surface is broken in the new model. Note that BIMx lighting settings like sun azimuth, altitude, brightness, SSAO or shadows seem to have no effect on the bug.

Can anyone shed some light on this issue?

Thanks for your time,

- Phil

[Anonymous]

Phil,
To me looks like the sun settings are different, shadows in different positions, the dark shape on the top of the water is s shadow.
Scott

[Anonymous]

sboydturner wrote:
Phil,
To me looks like the sun settings are different, shadows in different positions, the dark shape on the top of the water is s shadow.
Scott

Unfortunately it's unrelated to sun settings. Azimuth, altitude, and brightness have no effect on the particular dark patch shown on the right side of that image, in the shallow portion of the pool.

[Anonymous]

philipviana wrote:
Unfortunately it's unrelated to sun settings. Azimuth, altitude, and brightness have no effect on the particular dark patch shown on the right side of that image, in the shallow portion of the pool.

Could you modify your screenshot to mark (circle) any areas you have a problem with?

We can see the difference between the two images, but they do have different sun position, so we have hard time comparing the two.