lstratto27
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Hi Guys,

 

I need help figuring out why my interior ray traces are all coming out grainy and pixelated? Does anyone know what settings I'm using that could produce this effect. Photon Mapping, Caustics, etc? I should mention I have X7 and leave my ray traces for 3-4 hours. I come back to an ok picture but they're still slightly grainy and pixelated. I've experimented with lighting, materials and settings. Watched tons of videos, searched the knowledge base and I still can't figure it out. Also, I sent customer support this question who referred me to the videos. Yeah... those videos are not updated (versions X1 and X3 are a bit different than X7) sorry customer support but on this one you were not helpful. At this point I'm very frustrated and have no clue how to fix this problem. I've spent so much time on this I could scream. Please help!! 

 

Thanks, 

Laura 

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Hi Laura, while I am no ray trace maven this topic

has been bandied about on the forums quite a bit.

If you use the search feature in the upper right hand

corner it will lead you to quite a few threads. Be sure

to change "this topic" to "forums". I entered " ray trace

settings" and got numerous results. This is one of

the better ones:

https://chieftalk.chiefarchitect.com/index.php?/topic/2803-raytrace-questions/?hl=+ray +trace +settings

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Laura - you should get decent results in about 10 passes or less.  IS your system old?  What kind of video card do you have?

I am no expert on equipment but it sometimes is at the root of the problem.  It is a good idea to make your equipment part of your

signature and post a picture of what you are getting. MAybe even post the plan for others to show what they can get in what time frame.

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Here are the settings that I have found that have a majorl impact on Raytrace times.

 

Enable Environment Light 

Photon Mapping

Point Light with (Soft Shadows)

 

On a simple plan with one light and these settings turned on a single pass took about 9 minutes. With them off a single pass took about 45 sec. That's more than a 10 fold increase in Raytrace time. I usually run about 10 passes, 90 minutes versus 7.5 minutes. Huge diff.

 

Graham

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Hi Guys,

 

Thanks for all the suggestions. I've been able to get them to look better but their still a little grainy after 3 hours. My computer is a new Mac OS X, has a great video card and is top of the line. Tried rendering with photon mapping with less lights and different preference settings. Like I said better, but still a bit noticeable. I'll post an update if I still encounter issues going forward. Thanks again for the advice. :) 

 

-Laura 

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@ TheKitchenAbode I think it was a total of 10 passes in that time. It's a really detailed kitchen though with lots of lighting and stainless steel appliances. Plus I'm using photon mapping to get my stainless steel to show up so that setting is suppose to take longer. 

 

On another note does anyone know what legacy shadows are (in preference settings) and what legacy compatible texture mapping means under default settings? Also anyone know what hardware edge smoothing does? Just trying to understand the settings and if they could help fix my problem. 

 

Thanks, Laura

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Hi Laura,

 

Never really played with the "Legacy" option but this term usually refers to a method that is considered as a standard that has been around for a long time.

 

Hardware edge smoothing relates to the camera view edge smoothing as you pan the camera. Hardware is faster than the software method but this should not impact on Raytracing as it is an independent program. Same goes for your graphics card, Raytrace uses your main cpu not the graphics card, it's really just a number cruncher.

 

Suggest you check your lights. If any are point lights with shadows on then your trace times will be high. Photon mapping turned on will also increase the time. Keep in mind that the time degradation is cumulative, more lights more time.

 

Suspect the pixilation is due to the photon mapping, 10 passes may not be enough to generate a clean pic. The Raytrace process is progressive, each pass refines the image. The visual impact of each pass follows the law of diminishing return, as the number of passes increase the noticeable improvement lessens.

 

If you need this level of quality then you may have no choice but to let the Raytrace run overnight to see if a higher number of passes will produce the result you are looking for.

 

One other item that will effect the time is the image size set in the Raytrace DBX, the larger the size means more pixels need to be crunched. Make sure the size is not unnecessarily high for the intended presentation.

 

Graham

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Thanks Graham, great information. Unfortunately, I've let some of my previously rendered images run over night and they look no different than hour 4. However, I'll check on some of your other suggestions and see if that helps. Thanks again!

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