over exposed population.

[Grassynoel]

Hi all. As soon as I put an .obj population in my scene, (xfrog or other) the render exposure blows out to flat white. The pre-compute which is normally all small pin pricks is peppered with larger dots like over bright samples and the render goes haywire. Any ideas on this?

Thanks

Glenn

[jo]

Hi,

The best thing to do would be to save the project file and send it to us. You should also include any models you've used in the scene. You can send it to me directly at:

jomeder@planetside.co.uk

Regards,

Jo

[Grassynoel]

Will do. I'm pretty sure it's to do with alpha maps. As soon as i turn the alphas off it's okay, but of course I then have squre grey cards instead of leaves. I'll bundle it up and send in a tic. Thanks.

Glenn

[Oshyan]

This happens with *any* population of any object? Or just vegetation objects?

- Oshyan

[Grassynoel]

So far it's been with Xfrog obj trees and trees ported from Vue. I think it's the alphas for sure.

-g-

[Oshyan]

What format are the textures/alphas? Have you examined them for any problems?

- Oshyan

[Grassynoel]

I've tried 32bit tiffs and 32bit tga's and they seem fine in photoshop, RGB+A.

[jo]

Hi Glenn,

You need to go to the shader for the leaf texture. Uncheck "Unpremultiply colour" in the Images tab and add the leaf texture image to the "Opacity image" param in the Opacity tab. Precise details of how to achieve this are left as an exercise :-), but let me know if you get stuck.

I should add it's the "Unpremultiply colour" setting which is causing the colour to blow out. You need to add the leaf texture image to the "Opacity image" param to make the leaves transparent in the right places.

Regards,

Jo

[Grassynoel]

Done!
Many thanks Jo and Oshyan for your time.
Seems to me that checkbox might be best defaulted to 'off'.

-g-