weird colors using GI

[noam_farhi]

hi evryone.
i have this scene i'm working on for quite some time now. untill now all went great, but lately when i tried rendering it i got many "matrial overbright or invalid colors" warnings and weird neon-like colors appear at what seems to be random spots on many objects. when i tried to render previous versions of the same scene (backups), it also happened, although these scenes used to render perfectly. other (less "heavy") scenes also render fine.
the spots occur in the same place on evry render, but when i reopen max and render again it changes.
i noticed similar posts regarding this problem. i tried the script that was posted and it didn't help, and i used no raytrace materials.
p.s. this doest happen when i'm rendering with GI off.
i think attaching a jpg would help, but i have no idea how to attach it here...
please help me on this one, it's most frustrating...
thanx

[prey1979]

i could be wrong but i had same problem of neon spots of random colour in my scene and goncalo had told me it was to do with using raytraced materials and that i should get rid of them.. and low and behold the master was right and i the student gained a little more info in the realm of vray... so just make sure ure not using raytraced materials..... i hope this helps let me know

[noam_farhi]

hi prey
i've seen some posts about the raytrace materials. the thing is, i have'nt used any, and even if somehow a raytrace material found it's way to my scene: there are many objects that recieve "the neon treatment", and it's impossible all theses uses this sneeky material. besides, i tried rendering some previous stages of the scene (which renered fine) and the problem occured again.
also - a few days ago, after many tries and restarts, it managed to render fine. but the day after that when i tried - there it came again.
another little experiment i did was to replace all the materials in the scene with the default material, and it renered ok.
did i mention there's no problem when GI is off?
oh, and maybe it's just me being paranoid - but i think my computer isn't working as fast as it used to. after checking my hard drive i've seen it's packed, but i emptied it by 20% and the problem remains. besides, i noticed i never run out of RAM while rendering (i have 1 G RAM and intel pentium 4 2.4), so i doubt that this is what causing this whole thing.
thanx

[Erik de Graaf]

Hi noam_fahri

I am new to vray and this forum and i recognize your problem, in my scene there were flat images with opacity materials (standard max).

When i replaced those materials with vray materials with refraction mapping my problem was solved, no more neon lights.

Maybe this is the same in your scene, hope this helpes you.

Regards

Erik

[davexl23]

Confirmed cure!

Okay - it seems that several things could be causing this problem, but here is one I confirmed as a fix.

Apply cropping to all bitmaps.

Opened problem scene - massive coloured GI splotches and warnings about overbright colours.

Used VArcht Tools maxscript to turn on cropping on all bitmaps.

Fixed.

This one has been dogging me for some time - partial fixes in the past that helped (but were not a complete cure) were:

* to tone down materials that had bright reflection maps (as opposed to raytraced 'natural" reflections)

* convert weird imported meshes to mesh, collapse all modifier stacks.

* increase GI quality settings.