Carpet (GI light blotches w/Displacement)

[KVMaster]

Messing around with carpet here. Using a Vray Displacement modifier with a texture map to make a carpet texture. Seems to work OK but am getting these light spots (look like footprint wear patterns ). Any comments on how to get rid of them? Better GI setting levels suggestions?



Image with GI irradiance map preset to LOW and HSph = 50 & Interp = 50

ftp://saec-kv.com/Forum/Carpet_Low_50x50.jpg


Image with GI irradiance map preset to Med and HSph = 100 & Interp = 100

ftp://saec-kv.com/Forum/Carpet_Med_100x100.jpg

[Bratwurst]

Umm.. I like the spots makes the carpet more real

[Robert]

Try Hsph = 20 & Interp = 80, then lower the values of the control thresholds.
The only thing else would be using direct comp or photons.

robert

[Gijs]

you might try to lower the noise treshold in QMC to 0.002 or 0.001. That could help.

Gijs

[flipside]

People seem to think that the hsph and interp value should be raised together and set to the same amount. Actually the opposite is true here!

Say you use low hsph=40. This means not very accurate GI calculations. To cover the inacuuracy, you could blur out the GI info. This is done by the interp value. It interpolates the lighting info in the neighbouring samples. So high interp value means many samples are blurred together, low interp value means less samples are considered during interpolation. hsph=40 and interp=20 will show many splotches. Hsph=40 and interp=100 will blur it all and in undetailed areas it will look like cleaner GI! But in detailed places you'll have very inaccurate lighting (for example small objects will float because all samples underneath it are blurred together with large areas around them).

If you use high hsph for example 80 or even 100, you do this to have better GI. Raising the interp value to 100 also will blur it all out, giving you a detailed IR map but an undetailed visible result! If you increase the hsph, you should leave interp the same or even lower it.

Say you want extreme detail under many many small objects. You would increase the hsph. But even if you increase it to 500, if you're gonna blur it out with the interp value you will still get no detail.

So for the carpet I think you'll loose the footsteps if you would render with hsph=100 and interp=20 or something. It will also render faster because less interpolation is needed.

Not sure if this will solve you're problem but anyway it's a common mistake imo.

Kind regards,

flipside

[Suiciety]

I have to agree with flipside.

A lot of people don't (yet) know the way these two go together.

It's better to leave Interp. samples low, and increase Hsph. Subdiv.

As already said, this will increase detail, and should (hopefully)remove
the splotches........

Alternatively you can oncrease the Irradience Map Max. Rate (First
Bounce quality), but this could slow down the process quite a bit....

Give it a bash......and good luck!