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Why is my render so Slow? (settings inside)


Aaron2004
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Hey guys,

 

Well, after many years of sitting in the sidelines, I've finally decided to bend over and buy VRAY. I've done a few tutorials, and I really REALLY like it. It sure is better than VRAY free.

 

The one thing I'm strugginling with is speed. I am getting fairly satisfying results for just staring out with it, but with awful speed. The picture I attached was rendered out at 2000x1300 resolution and it took 13 hours...with an estimated 20 more.

 

I have attached my settings. Do I have any certain subdivision cranked up WAY to high? Asside from the wierd blocking in the carpet, there is hardly any noise in the picture.

 

 

Thanks!

 

Aaron

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Well, since you're used to VRayFree, a couple things I'd ask:

- are you using VRayMtl instead of the regular Standard Mtl+VRayMap?

- are you using VRayLights?

Other things you could check:

- try using IrrMap at Medium with 60 for Hemisph. Subdivs. 20 is too low (I myself use 30 for quicktests only)

- try Adaptive Subdivs instead of Adaptive QMC. It looks like you don't need QMC there.

- On LC, set the number of passes to the number of processors you have (probably 2). Also, check "use LC for glossy rays" and Adaptive Tracing.

- Double your Noise Threshold

These are the things I can think of for the moment. Try those and see what happens.

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Thanks for the help, Guys.

 

I did what you said and set it to render for my half hour lunch at 320x240 resolution. It only took 20 minutes. Hopefully doing it at 2000 resolution won't make it exponentially slower tonight.

 

One more quick question...I wonder if anybody else expereinces this also. Ever since I got VRAY, VIZ goes really slow. My scene is high in polys...but even when I hide everything, things just go slow. I have a newer Dell Xeon Workstation, and things haven't been slow until I got VRAY. Because the material editor takes so long to load, I wonder if it's the materials.

 

Thanks!

 

Aaron

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my 2 cents...

 

the filter type you use should be guided by what you want...if you want sharp, go with catmull-rom...if you want a softer feel, then area or mitchell-netravali are good choices. the vrayLanczos would be a good choice as well and often 10-20% a bit faster than each of these.

 

I definitely would take IR map off high and reduce to at least medium. If you're trying to shave time, you always start low and solve problems that arise rather than starting with high settings that overkill. You might find that a Low preset produces the same quality as Med.

 

Although Rick brought up some good points, i would be careful of the 60 subdivs. Again, I recommend starting low, with 20 and solving problems, if any that come from using these settings. A value of 60 could easily double the IR map calc time.

 

Light cache subdivs probably doesnt need to be so high either...start with 500 and work up from there... a setting of 500 can potentially result in 1/4 the number of samples...a lc with a value of 500 could be created in 1/4 the time that a lc with 1000 (potentially)

 

I think qmc will work fine in this case but you should start with a something like a 1,6 min,max rate, and work up from there...increase only if you are losing fine detail

 

If you havent done so already, definitely run the VRay Scene Converter feature to get all your materials and shadows converted

 

Why do you have a primary bounce of 1.5? That to me is a wasted effort. If you're going for a brighter scene (which using 1.5 gives you), you're doing it the hard way. Reduce this back to 1.0 and increase the illumination in less expensive way, like color mapping.

 

I would return the noise threshold down to 0.01 and again, decrease if problems arise

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i think you meant to say primary...but nonetheless, no you can't equate the 2 that way. But it's pretty simple...render a small region and adjust the color mapping until you get the illumination levels you want. My personal favorite is Reinhard (with a Burn value of 0.5) which is a mix of exponential and linear. Adjust the Burn value closer to 1.0 to make it more linear and adjust closer to 0.0 to make it more exponential.

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  • 4 weeks later...

Hello,

very interesting post guys,

I am just wondering: if vray is so genious /spectacular GI tool, so WHY so many people have so many problems using it? and why everybody newcoming to it is looking for clear convincing tutorials inspite of chaosgroup help/forum page?

I also use vray and noone ever has taught me in simple words how to use this tool step by step, although I paid for it, didnt't I?.

good luck

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hey Piotr,

 

I have to agree with you, yes vray seems so ultimate, you can push out astonishing renders, but in each render how much time is being waisted on additional tweaking, every render has some imperfections that you always have to go around fixing it, I am not even gonna mention animation,

I see how a lot of people bad talk Maxwell, but to produce single shot renders

it takes a lot less time, when you add your render time + double the time tweaking in vray. Some scenes examples can not be flawlessly rendered, what forces vray user to Photoshop retouches. I am dealing with a scene, that everytime I change lc subdivisions I get strange bright spots, and each time I increase the values or decrease it the spots show up in different areas.

I desided to forget further tweaking and go with photoshop to improve my render.

and Yes if the plug is so great why so many users have so many problems with it?? what is the average time frame in learning curve in vray?

and Every release of vray seems like a experimental plug, based on userss reports of it's mishapps.

 

Cheers.

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Vray isn't the issue, its the people using it. I'm not going to sugar coat this, there are a lot of amateurs who think that 20 minutes of playing with buttons will get them a front page worthy render. That ain't going to happen. Vray can only do so much work for you, you have to do the other 99%.

 

If you take the time to learn the software, and there are 2 great DVD's from the Gnomon Workshop that cover all things Vray, you can as well create some decent looking images. Though in the natural process of learning, you'll create some turds of images as well. That's just part of the process. You have to learn to walk before you can learn to run.

 

You are not going to get something for nothing. Just because you have Vray does not automaticly make you to world's best rendering God. All of the little tweaks you make in the first few times uising Vray you should hopefully be learning a little bit about what does what, so when you get a little more familiar with the system you can crank out renders in no time flat.

 

Vray (as is any CG package) is an always ongoing learning curve, as soon as you think you've mastered it, there is always more to learn.

 

Plain and simple, take the time to learn it. Start by reading the Vray help doc that comes with the system, and post/read on the Chaos forum which has a little bit broader of a knowledge base than this forum.

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The Chaos manual is really inadequate.

a great way to learn is from people who already know, you should check out the Visualization Insider series on cga : http://www.cgarchitect.com/upclose/VI/default.asp

with a great section on vray critical settings. Also, the author, Brian Smith is now teaching some fantastic webinars, which are definitely full of more VRAY information & help than you can find anywhere else:

http://commerce.vismasters.com/catalog/viewproduct.aspx?product=4383

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