Image map slows render by x4!

[mcvltd]

I've got an image map (below) mapped onto a mattress in an interior scene. The camera moves into the room and over the bed.

Render times when the mattress isn't in view are about 20mins.

Render times when the mattress is in the distance is about 35mins.

Render times when the mattress covers 1/2 frame is about 2hrs!!

I'm using a 1000x1000 version of the image below. Have tried it as a jpg and a tga with alpha - same results.

There are other maps in the scene (loads of leather mapped onto the walls) which don't have the same problem - they render like the wind.

Does anybody know why just this one texture map could cause so much grief?

Thanks,

Rob.

[Candelero]

Any displacements on the mattress ?
Can you send me the scene to look at it ?

Best regards,
nikki Candelero

[percydaman]

in certain situations, vray does NOT render opacity mapped objects very fast.

[mcvltd]

Percydaman - I don't think it's an opacity problem cause I tried the same map as a jpg without the alpha channel. Same sort of results.

Nikki - no displacement or bump on the mattress. Thanks for offering to have a look at the scene but client wouldn't be too happy (nda etc...).

Have just got the render time down to 1hr 16mins by deleting all the geometry and lights that can't be seen by the camera. The last 400 frames of the animation are in the aft cabin of the yacht and none of the other cabins can be seen. How odd.

[DanielBrew]

Bit of a stab in the dark here but it could be something to do with antialiasing the texture. If you've got time render a test image with antialiasing set to none.

Dan

[gunny263]

How about just posting the bedspread object so someone can help diagnose the material? That wouldn't violate any nda as long as it wasn't with the fabric designer.

[SnipeyX]

I don't think it's an opacity problem cause I tried the same map as a jpg without the alpha channel.

Did you still have the map in the opacity of the material? With the proper bitmap settings even a JPG will produce transparency (put the JPG in the opacity slot and set it's mono channel output to RGB intensity.) So if this was the case, it would come back to being transparent. May or may not be causing your rendertimes, but FYI.

[mcvltd]

I just put the map in the diffuse channel. With the jpg it had no alpha channel - with the tga it had. Didn't think of using the opacity channel. But you are right, it's not the cause of the problem.

No point in posting up the material now, I've found the culprit!

After having a play with switching aa filtering on and off (no real improvement - for both map settings and render settings) I began to play with different image samplers.

I was using 'adaptive subdivision' because in my tests it was giving a smoother, less-speckled render. So I went back to the vray help files and read 'However, with detailed textures and/or blurry effects, it can be slower and produce worse results than the other two methods.' Sod. Why didn't I read and understand this before posting?!

So I tried 'adaptive qmc' and it just ripped through the render with no problems (although it was more 'speckled').

What a discovery to make at frame 1128 of a 1500 frame anim! I'll put this one down to experience. Thanks for the help chaps. I'll use adaptive qmc next time!

Rob.