od[forum] > Spray Cans

JDenker

Mar 15 2008, 01:22 AM

Hey Guys,
i took a look at the PBR-Render Settings today... and this came out:

I was wondering about the light tiny dots that showed up all over the place? Is it because i have a low sampling or what causing it?
I'm pretty interested in your suggestions.
Thanks.

Cheers

-J

mark

Mar 15 2008, 05:31 AM

yes increase the sampling rate in the sampling tab of the ROP. 24 or 32 seems good.

stevenong

Mar 17 2008, 08:24 AM

Hi there,

First of all, how long did the render take?

Looks like you have depth of field turned on which is something I haven't tried.

If you're referring to the small bright spots, this is taken from the "Troubleshooting" section of the online PBR (http://localhost:48626/rendering/pbr) help:

CODE

Troubleshooting
White speckles

If you have white speckles in your image, you can try to fix it by limiting the number of color contributions a pixel will accept.

On the output driver Properties tab, add the mantra9.0/render/Color Limit property (see properties for information on how to add properties).

Decreasing this value is a bit of a hack: it can eliminate white speckles by clamping the amount of color contributed to each pixel, but it thereby darkens the image overall, and decreases the accuracy by truncating color contributions instead of distributing them equally.

Hope the above helps!

Cheers!
steven

JDenker

Mar 17 2008, 11:41 AM

thank you steven. the render took quite a while.. i fired up a new one on the weekend with more samples.. like mark suggest me. i watched the render the first hour, then decided to go home because it was 4 o clock at the night on a saturday. i totally missed setting up a verbose output that night. so i cant really tell how long the new render took. im guessing about 5 hours with is pretty long. i will start a new one this afternoon. thank you for the advice with the color limit property steven.
in the attachment you will see the render i took overnight on the weekend with more samples. i still need to work on the reflections from the plastic i guess.. also the reflections of the spraycans in general are a bit too strong in my eyes. so still a little bit of work till its done. I also have to say, this i my first render in houdini ever so i really appreciate your help.

Cheers

-J

rob

Mar 17 2008, 05:29 PM

QUOTE

Troubleshooting
White speckles

If you have white speckles in your image, you can try to fix it by limiting the number of color contributions a pixel will accept.

On the output driver Properties tab, add the mantra9.0/render/Color Limit property (see properties for information on how to add properties).

Decreasing this value is a bit of a hack: it can eliminate white speckles by clamping the amount of color contributed to each pixel, but it thereby darkens the image overall, and decreases the accuracy by truncating color contributions instead of distributing them equally.I may be way off field but would it help if you blurred the HDR , so theres less colour

I may be way off field , but what would happen if you took the HDR and blurred it in HDR shop before using it , then there's less colour contribution to give the pixel in the first place me thinks. Ive never tried it in Houdini with mantra but who knows it might or might not help

R

JDenker

Mar 18 2008, 12:03 AM

also, here is the render which i did on the weekend.

Cheers

-J

Jason

Mar 18 2008, 08:06 AM

Looking good:) I really like the composition, by the way. It's a pity that PBR doesn't yet have a sub-surface solution - but you might be able to modify the shader for the plastic cap to be able to receive some light from the back side - to emulate a thin transmissive plastic material?

LEO-oo-

Mar 18 2008, 08:46 AM

Yup - nice! I agree with Jason - nice composition!

cellchuk

Mar 20 2008, 04:23 AM

Good one..