Vray questions

#1

I’m working on my current book cover assignment, and have run into a couple of problems. Is there a way to set Vray to do a quick and dirty render. As it is, the scene I have is talking about an hour to render, due to displacment, unloading geometry, havinf water and such like. Now once the scene id done, I don’t care if it takes 2 or 3 days to render. That’s why I got a laptop. But it sure hangs up my working time. And since the scene is in a forest, I haven’t even added trees and bushes and ivy details and such yet. Just my main subjects. Nor have I added lights. I know I’ll have a main Vray light as the main, though I want the scene somewhat dark and foresty. I’ll also have at least two omnis or spots to shed a little more glow on a couple of things in the scene that need it. I know all that is going to add more time. So can I get a quick and dirty render, just to check on placement and such? It’s a pretty complex scene.

My second problem is that I went to add Vray hair and fur to my ground mesh to get a little grass. And for some reason, the fur sprouted from the bottom of the object. What? I don’t have much experience with fur yet, but I’ve never encountered this before. I did notice the gravity was set to -3. Is that a factor? Does anyone know what’s going on?

#2

It is pretty hard to give you any advice without knowing your render settings :hmm:

But if you have a lot of displacement going on, it is not unusual to get high render times. Try to use the VRay-Displacement Modifier with 2D-displacement. It is a lot faster.

In general I would setup the complete scene (object placement, lighting, shading …) without any displacement. So you get fast preview renders. When the scene is ready test render only small parts of the scene with displacement enabled, to see how it works out and tweak the settings.

I have no experience with vray fur, but perhaps the normals facing in the wrong direction.

Hope this helps.

#3

Without your render settings and scene setup its actually quite difficult to say. But ya as Ralle said, use VRay Disp Modifier instead of Vray Mat Disp. And its also depends on how complex your disp map is. Just try with these things for the test renders, it may help you… Set your Reflection Depth to 2, Set you Noise Threshold to 0.05 or something and most important is the maps you are using. Just check them through the Asset Tracking and make sure that all the maps are in the same folder and the paths are also the same. It helps a lot in loading and unloading of maps. Just try these, it may help or if possible try sending your setting.
All the best…

#4

Thank you very much. That was a very valuable tip for me. I tend to use a lot of displacement. I didn’t even know there was a Vray displacement modifier. That solved several problems for me. I still have to render my scene in layers and composite them in photoshop. That’s okay though, that’s easy. I was getting memory exception errors and much unloading of geomety. This tip fixed that. Plus I had an object in the scene that Vray REALLY didn’t like for some reason. I’ll have to figure out a way to make the disp mod work for me because I didn’t see any way to tile the maps. Plus, I tend to use a lot of blend maps, and I have learned that Vray doesn’t like those at all. That’s okay, though. I learned a long time ago how to make blend maps into texture maps. It’s one of my texturing secrets. So that’s not a problem. I still have to learn more about lighting with Vray, though. I’m still struggling with that. Plus, due to another large project, this is the first work I’ve done in like 6 months. But thank you so much for the tip.

#5

Nitesh, I missed your comment about this the first time around. You said make sure all the maps are in the same folder. Is this an important thing to do? I have gigs of maps in my library, all separated into the various types, like ground, stone, etc. I could easily put the scene maps in the scene folder. Does this really save a lot of effort from Vray? I ask because I’ve never heard this before. I haven’t been using Vray that long, even before I took the 6 month break I was still learning it.

#6

well just off the top of my head my quick and dirty vray settings are from default change: primary GI engine irradiance map, secondary GI engine light cache. irradiance map preset to low, put the hsphere subdivs to 20 and the interpolation samples to 10. turn on show calc phase and show direct light. switch sample lookup to overlapping. put light cache subdivs to 250 and turn calc phase on. you can also switch off displacement in your global switches :slight_smile: another tip is to use the override material, this replaces all the shaders in your scene with one (say a grey diffuse) so you can check lighting. It only does this at render time so it won’t do anything to your scene. Make sure you’re only using vray materials, vray lights etc (ok you don’t really have to but it’s a rule i go by). also with regards to object that you thought vray had a problem with, it might be that max has a problem with it. sometimes objects get corrupt especially if you’re transferring files a lot. they can be a mission to fix and sometimes you have to redo them =\ and just to concur with what other people have said, only use the vray disp mod for displacement maps :wink: with regards to the fur, vray fur isn’t really… furry =\ but it might be your normals with regards to your problem, try adding a normal modifier and flip the normals before adding the vray fur. hope that helps a bit!

#7

Good to hear that things are working for you…

As i said keeping all the maps in the same folder and applying it through the same path makes lots of difference in loading and unloading maps. Coz then max will search in a single folder for the maps and not in every single folders.

If you are working on a single com, that might not show u much difference. but if you are using network rendering, it actually makes a difference. I have faced the same problems many times. It has worked for me. Infact if you have maps on different comps in the network, it takes more time to even save the file, and if you move it to a single folder, it will save much faster.

#8

This is absolutely NOT true!
You can have maps in multiple folders, just make sure there are not any missing maps as max will try to find them in the folder where you opened you max file from and also a couple of other folders you may have specified. This searching time is negligible and dose not affect the loading/ unloading of bitmaps that vray performs.

I would make sure you optimise you bitmap sizes… most people think they neex 8k maps when really a 1k or 2k map is fine. Try halving all your maps sizes (save them to a different file name) and seeing if it makes any noticable difference. if it does, chuck the hires maps back only on the objects you notice are lower quality

#9

You might be right… but i have faced these problems many a times when my maps are distributed all over the place in the network… It might be a network problem… but when i have placed all the maps in a single folder… it helped me a lot… but thanks for your comments… it may help me check… if its true or not…

#10

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