Horrible, grainy shadows Keyshot to Zbrush

BobbietheJean · February 02, 2015, 09:52:26 PM

I just purchased KS for Zbrush and I've been having this issue with horrible, grainy shadows. I've tried lowering the poly count, futzing with the settings, different lighting and materials- all to no effect. Here is an example: http://bjpentecost.deviantart.com/art/Temp-Post-1-153117513 The model is a work in progress and I decided to test the new KS with it. I was horribly disappointed. As you can see, the leather renders up fine but anything in shadow stays grainy forever no matter how long I wait. I tried a number of different models and it seems like anything directly in shadow stays grainy forever. I can let it sit for ten minutes and the shadows will still look like total butt.

I'm running Windows 7 64bit, Nvidia GTX780, i5core with 16GB of RAM so my system shouldn't be the problem. I really have no idea what could be causing this issue. I'd deeply appreciate some help.

OK · February 03, 2015, 01:25:11 AM

Is the result smooth if you render it with the advanced settings instead of just letting it sit?

richardfunnell · February 03, 2015, 04:08:22 AM

It may have to do with your material sample settings. What material are you using for the face material?

BobbietheJean · February 03, 2015, 04:14:53 AM

QuoteIs the result smooth if you render it with the advanced settings instead of just letting it sit?

Nope. I've tried it with background render mode and the shadows still look grainy.

QuoteIt may have to do with your material sample settings. What material are you using for the face material?

I was using hard plastic but I also tried a few other materials as well and still had the same problem- the face stays grainy while everything renders pretty fast. So basically, with a little experimenting, I've concluded that it's not a problem with materials or this model. It seems to be a problem specifically with shadows. I could be wrong but it seems not.

richardfunnell · February 03, 2015, 04:22:42 AM

OK, so increasing the sample value on your material would be my first suggestion (regardless of material type). This setting is usually hidden under the "roughness" dropdown.

Try setting it to a higher value, somewhere between 16-32 should help with the material.

Rex · February 03, 2015, 08:33:31 AM

The model looks pretty complex and your machine is only 4 cores so the shadows will take some time to resolve. Did you try increasing "Shadow Quality" in the project>settings tab? This will improve the shadow quality in the realtime view and when using max samples or max time mode. Advanced control has its own shadow quality control.

BobbietheJean · February 03, 2015, 01:55:59 PM

QuoteThe model looks pretty complex and your machine is only 4 cores so the shadows will take some time to resolve. Did you try increasing "Shadow Quality" in the project>settings tab? This will improve the shadow quality in the realtime view and when using max samples or max time mode. Advanced control has its own shadow quality control.

I've tried cranking up the shadow quality and it seems to have no effect. I can let it render indefinitely and I will see little to no quality change in the shadows. I will try to post an example later.

QuoteOK, so increasing the sample value on your material would be my first suggestion (regardless of material type). This setting is usually hidden under the "roughness" dropdown. Try setting it to a higher value, somewhere between 16-32 should help with the material

I'll try that and see what happens.

BobbietheJean · February 03, 2015, 05:30:11 PM

So far, none of these suggestions have worked. I gave the model to a friend who also has KS and he has the same problem. Bad shadows, especially within the hood and especially under the neck. So far, I have tried a wide variety of different settings, materials, and lighting set ups.

Edit: After some experimenting, I have concluded that this seems to be a problem with the live render window. These issues *appear* to vanish when using the render option rather than the live window but only if I crank up the samples. This is kind of disappointing. I don't remember having this problem when I futzed around with the KS demo before.