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Light Cache Extremely slow all of a sudden


ivanjay
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Hello,

 

I am still working on my first vray render. Everything is coming along when all of a sudden my light cache is now taking forever to calculate. It went from take 7-8 minutes on a medium setting to 8 hours. It is taking 20 minutes with the settings all the way down.

 

I did add a bunch of geometry and materials but my model is fairly simple so I think something must be wrong but I cannot figure it out...

 

The file is too large to upload but easily emailable. If anyone can take a look let me know and I will send it to you.

 

Thanks so much!

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I'd be glad to take a look at it but I think I can help: When this happens to me it is because of one of two reasons.

1) Displacement is on and it is affecting the light cache time heavily. To test this theory turn off displacement in your render settings and give it a go again.

2) I have a map that is not made for vray in the scene somewhere. If I forget to assign a material to geometry imported from autocad then it by default gets a material called "Global(Architectural)." When this happens my light cache starts to take a lot longer to calculate. Go to your material editor and go to "get material" and select the radio button on the left that says "scene." This will list all the materials in your scene. You can see then which ones are and aren't vray materials.

 

Hope this helps.

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I'd be glad to take a look at it but I think I can help: When this happens to me it is because of one of two reasons.

1) Displacement is on and it is affecting the light cache time heavily. To test this theory turn off displacement in your render settings and give it a go again.

2) I have a map that is not made for vray in the scene somewhere. If I forget to assign a material to geometry imported from autocad then it by default gets a material called "Global(Architectural)." When this happens my light cache starts to take a lot longer to calculate. Go to your material editor and go to "get material" and select the radio button on the left that says "scene." This will list all the materials in your scene. You can see then which ones are and aren't vray materials.

 

Hope this helps.

 

Neither of those seemed to work. I did see a Global (Architectural), i loaded that map into my material editor and changed it to a default VRay material but to no avail.... Is there a way to see what geometry that material is assigned to. All of the naming is generic since it imported from CAD so I cannot tell what is what...

 

If you can send me your email I will send you the file...

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Even though you've said you're not using displacement, I often find that its either displacement or fur that pushes up a LC calculation to these kinds of times.

 

Just to be 100% sure if you haven't tried already, turn off the displacement global switch and try again.

 

Perhaps you could upload a test render using BF instead of LC for the time being along with screen grabs of your settings.

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make sure you have no completely white materials in the scene (RGB 255,255,255). This can sometimes lead to secondary bounces going off on one, bouncing around almost indefinitely.

 

A good quick test to see if it is a material rather than geometry problem is to stick a simple grey vray material into the override slot.

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looks fine to me, though you might want to turn off reflective GI in the indirect illumination dialogue, generally doesn't add to much illumination unless you've lots of mirrors or specular objects in the scene and it can increase render times a bit, not as much as you've described though so I still suspect a dodgy material in there somewhere..

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check motion blur isn't turned on, or DOF for that matter, in the camera roll-out.

 

Both are unchecked.

 

If anyone wants to provide their email I would gladly send out an archive of the file so you can see what I have going on. I am now at a complete standstill...

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does the text above the progress bar ever say unloading geometry whilst calculating the light cache? If so your dyanmic memory limit is set too low, switch to static (settings>system) or raise the memory limit to 2K or thereabouts if on a machine with 4 gigs of memory.

 

Would take a look at it but running good old max2009 here so I'm afraid can't really help on that score.

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does the text above the progress bar ever say unloading geometry whilst calculating the light cache? If so your dyanmic memory limit is set too low, switch to static (settings>system) or raise the memory limit to 2K or thereabouts if on a machine with 4 gigs of memory.

 

Would take a look at it but running good old max2009 here so I'm afraid can't really help on that score.

 

I did not see anything that says unloading geometry... Just Building Light Cache.

 

I bumped up the dynamic memory limit to 1800 since I have 4 gigs but on a 32 bit machine so effectively 3 1/2 gigs.

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its displacement or you just imported loads of heavy geometry

how many polygons is your scene

 

From polygon counter 115,834 polygons. Everything is modeled in Architectural Desktop and rendered in Max except for a few items I purchased from 3dstudio.com

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Well you appear to have ruled out the possibility of it being a materials issue. So then it must be some geometry in your scene. Probably the easiest thing for you to do will be to use some process of elimination. Hide everything and then unhide objects one by one doing test renders in between. Your problem object ought to become very apparent after that.

 

E

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Well you appear to have ruled out the possibility of it being a materials issue. So then it must be some geometry in your scene. Probably the easiest thing for you to do will be to use some process of elimination. Hide everything and then unhide objects one by one doing test renders in between. Your problem object ought to become very apparent after that.

 

E

 

I am getting really confused now.... Most of my light cache calculations sit in the 45-55 minutes modes except when I turn on the walls, millwork fascia's, and floor. However, that is 2/3 of the model. There is no way any of that geometry is creating all of the issues....

 

Any ideas on how to identify this or should I start swapping materials to mental ray and see what happens...

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I am getting really confused now.... Most of my light cache calculations sit in the 45-55 minutes modes except when I turn on the walls, millwork fascia's, and floor. However, that is 2/3 of the model. There is no way any of that geometry is creating all of the issues....

 

Any ideas on how to identify this or should I start swapping materials to mental ray and see what happens...

 

You've already done a render with a plain white vray over-ride material correct? If your light cache times are still high (even 40-50 minutes is high IMO) than it's most definately a geometry issue. I'd bet a crisp American $20 bill it is...

 

E

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You've already done a render with a plain white vray over-ride material correct? If your light cache times are still high (even 40-50 minutes is high IMO) than it's most definately a geometry issue. I'd bet a crisp American $20 bill it is...

 

E

 

The floor seemed like it might have been causing part of the issue....

 

I deleted the floor I modeled in CAD and made a new patch grid in Max and applied my floor material. It does look like that has helped somewhat.... Next it seems that my walls are screwed up.... So I guess I need to delete walls out of CAD and model in max...

 

Why would they all of a sudden be going screwy on me? I personally prefer modeling architecture in CAD since we have Architectural Desktop and it is a lot less clumsy.

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Good news, I have finally figured it out! Hiding behind a glass door in my overhead cabinets where coffee mugs that evidently for some reason where tremendously large in polygon count. I removed, remodeled and went from 200k plus polygons to 18,000. BIG difference!

 

Now I am trying to figure out my exposure as I moved sun multiplier to .1 to fix a sky issue and my model is now dark as could be.... grr another challenge

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