white dots!!!

[juan.carlos.rioja]

Hello guys

Some time ago, white dots started appearing on my renders. can someone explain me why???

...

can not post the image because the folder is full so i hope some of you guys had the same problem before...

thanks

[juan.carlos.rioja]

Re: white dots!!!

[juan.carlos.rioja]

Re: white dots!!!

there's my image... so i hope anyone can help with this... :-\

[dalomar_cg]

Re: white dots!!!

In the Color Mapping rollout there are two options...Clamp Output and SubPixel Mapping...enable both of those and you should be fine.

[juan.carlos.rioja]

Re: white dots!!!

thanks dalomar ;D ... one more question what does those options do???

[dalomar_cg]

Re: white dots!!!

My short answer before hinted that its not a quick explanation, so now that I know you want it, here it goes.

V-Ray calculates images in float point format, meaning that rather than represent color from 0 to 255, it thinks about it on a scale of 0 to 1 in decimal format. There are many advantages to this (accuracy being one), but the main thing that this allows is for color to be "brighter than white" which would translate to a float value beyond 1. This is great because the retention of that extra data can be very useful for creating realistic images and doing post work. The down side of that is that sometimes, due to certain "idiosyncratic" samplings a pixel may proceed beyond white when its neighbors don't.

The solution I suggested to you does two things...the first one, Clamp Output, makes it so the V-Ray doesn't output images beyond 1 or pure white. The reduces the chance that any of those samples will become so bright that they throw off a given pixel. The second setting, SubPixel Mapping, performs that test on a per sample basis...meaning two things... first that once the value of a pixel reaches the maximum (1) the calculations are stopped, thus saving time...second that individual values that are beyond 1 are managed much better.

That didn't turn out to be as long as I thought it was going to be and hopefully that all makes sense. As a side note, the downfall of using clamp output is that you won't be able to do as much exposure adjustment as before...something to keep in mind

[luchangliang_cg]

Re: white dots!!!

Thanks for your answer too, I have the same question ,hah. :P