Devin Johnston Posted March 9, 2007 Share Posted March 9, 2007 I'm trying to understand color mapping in Vray, some things I've read say to use Gamma correction, others say use Linear multiply on interior scenes. Right now I'm using Linear with my dark and bright multiplier set to 1 and gamma set to 2.2. This looks pretty good but I'm finding that any materials I add to the scene must be "gamma adjusted" before they display properly. I've tried changing my settings by setting Gamma to 1 and dark to 2 and bright to 1.5 which also seems to work. So basically I don't know what I'm doing and I don't understand these settings so can someone smarter than me explain what I'm doing and how this works? Link to comment Share on other sites More sharing options...
BrianKitts Posted March 9, 2007 Share Posted March 9, 2007 leave your bright/dark alone (1)... the rest your have correct. in max preferences though..... set it like the attached image to correct your bitmaps and color shaders.... Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 Can you explain to me why I have to adjust everything to a 2.2 Gamma? Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 9, 2007 Share Posted March 9, 2007 This gets into the whole 'linear workflow' thing, and perhaps we should all go back and re-read that mind-bending thread. I don't know if Max renders to a particular gamma. C4D renders to 1, which is the basis for the linear workflow. But beyond that, I find that use HSVexponential for colormapping usually works best, and always leaving the dark at 1, and having the light at either 1 or sometimes as much as 1.66 Testing a few low-res outputs should help you decide an the bright setting. Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 Ok guys since I've got you here tell me what you think about this scene. It's got over 3 million primitives and takes about 28 minutes to render using low settings in both my IR and Light Cache engines. This is a single frame from an animation so render times are kind of important. I'm still doing better than Maxwell which would probably be like 6 hours. Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 9, 2007 Share Posted March 9, 2007 It's got over 3 million primitives and takes about 28 minutes to render using low settings Is there a part of the scene we aren't seeing, like a few thousand poly-trees perhaps? If that's 3million polys then you need to optimize your geometry. I haven't used vray or mentalray yet so I don't know to what extent so many polys affects it, but in most engines fewer polys helps a lot. Are you excluding tiny and shiny stuff from the GI-type calcs? Also--get some color in there. Perhaps as simply as forcing environmental lighting to the blue and the chandeliers to the yellow. Maybe turn up the color on the materials and up their color bleeding a little. Give colormapping some color to map. Link to comment Share on other sites More sharing options...
AJLynn Posted March 9, 2007 Share Posted March 9, 2007 The thing with Vray is, there are ways to reduce the impact of high-poly scenes to almost nothing, especially if you have repeatable objects. E.g., with this scene, each of those chandeliers could be made from a pie-slice of 1/8 of the fixture, 8 instances, in polar array about the center. That would make Vray very happy. Also, if you do have a few dozen trees off camera, you can convert them to XRef'ed Vray meshes and speed things up a lot. Link to comment Share on other sites More sharing options...
BrianKitts Posted March 9, 2007 Share Posted March 9, 2007 ...... you can convert them to XRef'ed Vray meshes and speed things up a lot. not to throw off topic but..... is there a advantage/difference in having your vray meshes xref'd in as opposed to just being converted to a vray proxy? Or are you just calling it an xref because of how the proxy works and not actually xrefing them into max from another file? maxer..... render settings could be slowing you down... it amazes me with vray that one wrong slider can be the difference between 15 minutes and two hours render times (slight exageration but it's almost that bad)... keep in mind when estimating your render times, that you will most likely want to precalculate your irradiance passes so that will help a bit on your render times. Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 This is one of the most detailed models I've ever worked on; most of the geometry is coming from the chandeliers (2.5 million faces). In Vray isn't there a way to instance objects so that their geometry doesen't affect the scene, is that what you were talking about AJLynn? I agree Ernest there needs to be more color but I'm having trouble getting the light levels high enough without washing things out. I'll try some of your suggestions. Here are my GI settings, please let me know if I can optimize them in any way. Link to comment Share on other sites More sharing options...
manta Posted March 9, 2007 Share Posted March 9, 2007 Your GI settings are low enough for a prewiew, but you're going to have to raise them alot when you're doing an animation to avoid flickering, so you need to get this time way down, how long does it take to render without the chandeliers ? And what resolution are you rendering to ? Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 Rendering with everything turned on takes 28 minutes on a dual processor quad core machine which is about 4 times faster than most of the machines on my farm. If I turn up the settings taking the IR to Medium-animation and the Light Cache from 350 subdivisions to 700 subdivisions my render time increases to 1hour and 5 minutes. Link to comment Share on other sites More sharing options...
manta Posted March 9, 2007 Share Posted March 9, 2007 Ok then, there must be something wrong, if you're using an 8 core computer and it takes 28 minutes to render that scene at low settings, without displacement or glossy reflections that's just crazy... Can you show your summary info, are you using opacity maps anywhere... are there a million seperate objects ? Link to comment Share on other sites More sharing options...
AJLynn Posted March 9, 2007 Share Posted March 9, 2007 Sorry, by XRef I meant proxy. (I always say "XRef" for things like that.) Anyway, yeah, Devin - instancing in general makes Vray faster, and exporting a Vray Mesh, proxying that in and instancing the proxy will make Vray and Max both run faster. I've done renders of scenes that other people modeled in Sketchup, with several million polys, by detaching the repeated parts, making Vray proxies and instancing them, usually the number of polys you actually need in the Max file is under 100,000 that way and it becomes very easy. Chris posted a render a while back that was over a billion polys, rendered on a P3 with something like 512MB RAM, in very reasonable time. Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 William I do have glossy reflections on all the wood materials in the scene as well as the brushed stainless steel and frosted glass in the chandeliers. Link to comment Share on other sites More sharing options...
AJLynn Posted March 9, 2007 Share Posted March 9, 2007 I'm actually embarrassed to have to ask this, so sorry Devin but I'm going to ask it in your thread instead of starting my own What's the fix for the problem (in Vray 1.5RC3) when you have a wood floor (with color, bump and glossy map) that gets really blurry as it recedes from the camera? I know I've read about fixing this more than once on this forum but I can't seem to find it. Link to comment Share on other sites More sharing options...
manta Posted March 9, 2007 Share Posted March 9, 2007 Ok, that explains some of it... Try this...go into the options tab of those materials and uncheck trace reflections, to tell the truth I wasn't sure that you were using any materials from that picture, so give that a try, and see if it has much impact on those materials... Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 9, 2007 Share Posted March 9, 2007 most of the geometry is coming from the chandeliers (2.5 million faces). Well that no good. You should knock that puppy down, smack it with a rolled-up newspaper and say 'bad dog'. Do you have a poly-crunching function in some 3D software? If not, send it to me (.3ds file) and I'll take a crack at squeezing the life out of it. Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 Ok, that explains some of it... Try this...go into the options tab of those materials and uncheck trace reflections, to tell the truth I wasn't sure that you were using any materials from that picture, so give that a try, and see if it has much impact on those materials... No luck, this time it took 30 minutes instead of 28 Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 I should have also mentioned that I have about 70 IES lights in the scene all with vray shadows turned on. Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 9, 2007 Share Posted March 9, 2007 I should have also mentioned that I have about 70 IES lights in the scene all with vray shadows turned on. That could do it. Many of those could probably do about 90% as well if they were regular lights. For a still you wouldn't worry about it, but for animation, every savings counts. Look at the IES lights, see if some could be swapped out for something more simple. On the polycount front--try turning off the chandeliers (but not their lights) and re-run a frame, see if it changes things much. If it does, poly crunch it. If it doesn't, you know its the IES lights. Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 Ok I've figured out where my speed problem is coming from, it's the IES lights. When they are turned on it takes about 3 times longer to render than when there off. I guess I'll try using vray lights and see if that fixes the problem. Link to comment Share on other sites More sharing options...
manta Posted March 9, 2007 Share Posted March 9, 2007 I should have also mentioned that I have about 70 IES lights in the scene all with vray shadows turned on. Umm...yes that could affect render times, are the lights necessary, it looks like the space is being lit by the sun ?? Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 They are mainly under the balcony but there also in the chandeliers. Is there a specific light that would work best in this situation? Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 9, 2007 Share Posted March 9, 2007 For chandeliers I usually make the lamps or shades self-illum with a gradient or map (just so they'll look right) and use one or two omnis in the center of the whole chandelier fixture. Link to comment Share on other sites More sharing options...
Devin Johnston Posted March 9, 2007 Author Share Posted March 9, 2007 Good trick Ernest I'll give it a try. Link to comment Share on other sites More sharing options...
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