Dotted particles

Hirokaz

Hi there. I just rendered some scenes overnight and the finished pictures have some dotted particles scattering around that look like it's not finished.

I know there's a special word for this but I don't remember. Please see attached picture.

I did it with Iray, the default setting. The scene only has HDRI and one figure.

How can I avoid these particles? My video card is Nvidia GTX 750 1GB. Should I get a better one?

Tobor

This is ordinary rendering noise, specifically pixels that haven't fully converged. Convergence takes longer in darker scenes, when there's not a lot of variation (wide swaths of skin), or when there's too much variation (metal flakes, or something with lots of very small detail).

If you used the default Iray settings, your render didn't go overnight. It stopped after 7200 seconds, or two hours. If you want it to go longer, adjust the time upward.

Getting a higher end nVidia card isn't going to improve quality, but it will render faster, as it'll have more CUDA cores to work with. 

Your scene looks a little bit dark. Try increasing the environment intensity, so that Iray has more light to work with. If you want the same overall look, decrease the exposure in the Tone Mapping settings. For example, try doubling the scene intensity, and set the f/stop from the default f/8 to f/11.

mjc1016

There is also a chance that because your card has only 1 GB of memory, it wasn't used at all.  So, in that case, 2 hrs is definitely not long enough...as without GPU acceleration, the renders do take several hours to complete.

Hirokaz

Thank you for your advice, Tobor and mjc1016!!

I'll try changing the Iray settings.

Tobor

To see if your card is contrinbuting to the render, and it's quite likely it's not, do a much simpler test render and let it finish. Choose Help->Troubleshooting->View Log File. Scroll to the bottom, and Daz Studio will have reported what devices were used to make the render. It should be clear if your 750 was involved, or if it just sat in the sidelines.

Hirokaz

Tobor said:

To see if your card is contrinbuting to the render, and it's quite likely it's not, do a much simpler test render and let it finish. Choose Help->Troubleshooting->View Log File. Scroll to the bottom, and Daz Studio will have reported what devices were used to make the render. It should be clear if your 750 was involved, or if it just sat in the sidelines.

I did a quick rendering and got these messages.

Iray INFO - module:category(IRAY:RENDER):   1.0   IRAY   rend info :     CUDA device 0 (GeForce GTX 750): 5 iterations, 0.168s init, 0.455s render
Iray INFO - module:category(IRAY:RENDER):   1.0   IRAY   rend info :     CPU (3 threads): 5 iterations, 0.022s init, 0.565s render

I suspect CUDA device 0 means my card was not involved.

What do you think? 

kaotkbliss

It looks to me like it ran 5 iterations with your vid card (computers always label things starting at 0, such as internal hard drives. The first is always "Logical Disk 0") before moving on to the CPU... But it would be strange that the render only went through 10 iterations so I could be wrong.

Tobor

That must have been a pretty simple scene! But it does show your 750 was rendering.

Now try it with your regular scene. It's possible Iray will skip your card, as it has only 1GB of RAM, but it would be interesting to test. You will definitely want to get a better card -- look for one with 4GB. Your current card has 512 cores, but they're wasted if the entire scene you're rendering won't fit into the card's RAM.