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Why aren't people using Mental Ray


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Invaderzim - great work,

 

yes glossies are a pain in the A** when it comes to rendering. They have become the "Flavour of the Month" and I have seen far too many renders where they have been used to the extreame and very badly at that.

 

This is my first real result frim Vray. There are some major issues, ie grain, light quality and something weird with the timber floor. This took 45 minutes to render and before I turned off all reflections 6 hours and counting.

the dark one is a straight render and the other is lightend and brightened in PS

 

JHV

 

Sounds to me like you may be doing something wrong along with the fact that you are not using a LWF. A scene like that should take no more then 10 min at high quality. Three questions... What version of Vray are you using? What settings? and do you have the scene and can I take a crack at it?

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Sure I will , I PM me and I will email you the scene.

 

Please excuse me, but what is LWF?

 

The settings I can remeamber off the top of my head are

Primary bounce - Medium (all the rest default)

Secondary - LC (Default)

 

I have been playing Vray and this scene with this for a week now and this was my best result. The worst was 10hours and still going. Most of my attempts have been stabs in the dark. I think the floor problem is due to a dodgy Material conversion and problably recreate it from scratch.

 

Thanks for any help and advice

 

JHV

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iani_3d I have been working through a few things on the scene. Part of the problem was some issues with glass elements in the windows and picture frames. Once I hide those then things improved. I can get fairly acceptable results quicker but they are too grainy. As soon as I bump up the settings the rendertimes go out the window.

 

My machine is a P4 3G with 1 gig of ram. Its not HT or anything fancy. This is why rendertimes are most important to me. Compare 1 hr @ 4000X2800with MR to that of 7 hrs @ 3000X2100 with Vray or even 5 hrs @ 4000X2800 with Brazil.

 

As I said before I am still learning Vray. Out of all the renderers I have used it is the most complicated, change one setting and it has impact over 10 others. Brazil was then next easiest after MR to learn.

 

JHV

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It seems to me you are starting at the end, and over complicating things for yourself, rendering out at such high resolution at such high levels might be the problem, how does it look at default settings at something like 800 x 600, and how long does it take...the reason I say that is because I always work from simple to complex, and only raise my settings as needed, you might have some settings 10x higher then they need to be, and you haven't even reached your desired lighting (I hope, cause its really dark)...

 

Most of these pics are done at default settings...

 

http://www.mantastudios.com/gallery-1/gallery1.html

 

:)

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Naturally I am testing and setting @ a lower resolution and with default settings. The image has progressed leaps and bounds since whats been posted here. I'll post the latest image tonight. At lower (500X4somthing) the renders are around 11minutes but still very grainy. I'll also post some grabs of the settings.

 

Its one thing rendering small and quickly, it is also meaningless when your final output it to print.

 

I have to chuckle to myself when ever I see tutorials that cheer and dance because they can render a very simple scene out at 300X200 in 20 seconds. This is precisly why I have used this type of scene. Its not overly complex but complex enough. There are some tricky areas to get light into and offers interesting material usage.

 

JHV

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When you said this:

 

"Compare 1 hr @ 4000X2800with MR to that of 7 hrs @ 3000X2100 with Vray or even 5 hrs @ 4000X2800 with Brazil."

 

Were you comparing the image you posted done with MR and AO ??

 

Against GI renders done with Vray and Brazil ??

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And I would again suggest using PPT for previews (takes like 4 min. to see how it looks) and saving your GI maps for re-use, will save alot of time, and you can probably get away with using your 800 x 600 maps for your 4000 x 2800 renders.

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Yes, but in my defence not exactly the ones that I have posted here, more the ones that I have been testing and comparing off-line. Once I have a complete test case for each I will put something together illistrating and quantifying my statement. At this stage I am not being completely fair on my Vray results as I know that my setting are not completely optimal.

 

I have been using the low res maps for the final high res one, but the grain is even worse. I have tried cranking up the LC samples from 1000 to 2000, with slightly less grain, played with the QMC , just upper the rendertime, not noise reduction. Upped the IR from default medium to high, once again a little improvement but crazy rendertimes. In my last render (once again not posted) I recreated the maps from scratch for the highres render just to see what the results would be. Much cleaner than those of the reused lowres

 

For the effert that is going into getting a semi decent render I am getting more grey hairs than I like.

 

JHV

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I found mr to be easy and fast (though still slower than fr OR vRAY) for simple arch viz (flat walls), but I do aircraft interiors mostly, and the curved walls are a different matter to render -mr sucked and took freaking hours and hours to generate FG map, then the renders looked crap! Disactivating FG or using the sketchy FG mode (what's it called again?) gave a rough idea of lighting, but when I switched back to full FG, it looked totally different, and pretty shit. Any time I got a good result and copied it in a similar scene, it came out completely wrong. I fought with it for ~6 months, constantly testing on our local renderfarm as well as at home (truly pissed off the wife!), did the Jeff Patton tuts, hung at XSIBase (NOT impressed with a SINGLE interior I saw, except a TV-lit night scene, which was excellent), and switched to Vray after a short intro by a new co-worker, and we're all sold -it's WAY faster for our usual 4k/300dpi prints, predictable, handles indirect light better than anything except Maxwell, and with light cache, you get almost instant lighting feedback, unlike FG Hell. I went through this with Max6, and found that my scenes that were almost OK in Max6's mr were total crap in Max7's version (3.4). I got black blobs and all sorts of shit and finally said 'fuck it', Vray and Maxwell, and that's it. Just my experience. BTW, AO at print res looks like crap, so it's not useable for some of us.

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Well I've been running a few tests too, I went back to a scene I had done a couple months ago to actually record my render times, well it was no surprize to me that this render was 7 minutes for 800 x 600 , low Irradiance maps, and LC set at default 1,000...

 

So I rendered at 4,000 X 3,200 and it took 2 hours, thats the other pic, a close up to show there isn't any noise that I can see...so the only thing I can think of is there must be something wrong with your materials, your scene doesn't seem all that complex, I'm using displacement for the carpet, lots of glass refractions and reflections, glossy reflections for the metal ect...

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I have managed to get the rendertimes down to 5 minutes for the light calculations, but then when I render the times shoot up, this is at 800X500.

So yes there must be something wrong with the material settings. Thinking back I must have cranked up a few of the glossy reflection subdivs. Don't have the scene in front of me now. This morning I was reviewing what I had setup to render overnight. I was dissapointed to find that it was still going. I noticed that the buckets would stick on the wood floor and race through the rest. I don't think that it will take long to track down the culprit though.

 

Whats interesting with this whole exercise is that I have inadvertily prooved my earlier comment about the learning curve of each of the renderers. To date I have found Brazil to be the easiest, then MR and Vray lagging way, way behind.

 

JHV

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Its also interesting, that I had the exact opposite experience finding Vray to be the easiest, Brazil wasn't too difficult, but for interior renders, it would be sooo slow...it just goes to show how subjective these things can be...

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You are right on there, this is problably one of the most subjective discussions in visualisation.

 

Good things I like about Vray - displacment, proxy objects, good light distribution. Strong community

Good things I like about Brazil - Brazil lights, materials, fast photons, easy to use, sky light, great for exteriors, one of the best image samplers around

Good things I like about MR - AO, can mix material types, large scenes, easy to set up, quick, unlimited render nodes, Free

 

Bad things about Vray - difficult to track down problem settings, steep learning curve, difficult to switch to a different render at any stage, reliance on VrMats for speed. AA is slow for good results.

Bad things about Brazil - QMC is slow, difficult to fine tune for interiors. can be unstable. no release date for Brazil2 yet

Bad things about MR - not enough documentation about advance shader creation. too robust and difficult to get the sublty of Vray and Brazil. Still no fully implemented into Max

 

Conclusion : I am glad that I have finaly made a start in learning Vray and am prepaired for the long learning curve ahead. For most of my work I will be sticking with MR and Brazil. Once I am fully confident with Vray and worked out a good, solid workflow into our pipeline I will incorporate it into production. Brazil2 looks and sound very promising and will heat up this debate even more.

 

This has been an interesting exercise, and given me an oportunity to put these renderers in a head to head battle.

 

Thanks to all those who gave help and advice,

 

JHV

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So I decided to give MR a wirl, and now I could use your help...

I think I may be on to something here, I think one of the reasons people find MR to be daunting is what just happend to me...

 

I simply switched renderers to MR, and converted my materials to standard, and my shadows to MR shadow maps,I turned on FG and left everything at default, and this is what I got after 23 min. of rendering, so right from the get go I have something unusable, this is in contrast to the vray render I did a couple posts back, which was also at defaults and came out quite usable and only took 7 min.

 

I was not diswaded, I knew I was on to something, I just need to raise some values, but which ones ??

 

I'll continue my findings in my next post

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So now in this one, I raised the size of the MR shadow map from 512 to 3000, that seems to have worked well, I also raised the samples in FG from 1000 to 2000, and raised the samples per pixel to 1 and 16, now though it seems that its foggy or over exposed, don't know it just needs more contrast...and I also have no idea whats going on with the chair, looks pretty funky...

 

Anyone want to point me in the right direction...

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Firstly dont use shadow maps, rather use an area light with raytraced shadows,

 

Drop the FG samples down (20 or so) and adjust your lights accordingly. Once you got your lights right, up the samples again. default is good though

 

Set the bounces to 5 , more if you need to

To smooth out the results up the filter to 3, don't go too high as detail will be lost

 

Play with Photons, the combination of photons and FG is good and quick. The decay setting has the most impact, the default of 2 is too high, try 1.5 and adjust to suit. Photon samples of 500 is high but robust.

 

Finally don't be afraid to use the exposure control of Logarithmic to play with the brightness and contrast.

 

JHV

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Do you have raytrace reflections on your chair?

 

The image sampler can be Min 1/4 max 4 (16 can be slow but clean)

Type Mitchel

Locked samples OFF

Jitter ON

 

also be shour that you have a deep enough trace depth and unless you really need 6 reflection bounces drop that down to 3 (huge speed up)

 

Also do you have a far attenuation set? If you want to use shadow maps this will improve its performance.

 

JHV

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OK, heres my first attempt. I decided to change the lighting mood for fun

 

23 minuts (8 minutes to generate to solution). I havn't touched the materials, and there are a few things that need fixing there. This is done with very low settings just to get the lighting right, I will crank them up and render over the weekend.

 

I won't be around until Tuesday so don't worry if I am not responding until then

 

Just a side note. Manata model was done with Max7 and I am using Max8. There are some major changes to FG and Photons in Max8 so some of the settings will be different.

 

JHV

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I really like the lighting Justin...

 

So I've been running more tests...the first one is my PPT preview which took 4 min. and told me my lighting was the way I wanted it...ya gotta love that feature...

 

The second pic is 45 min. render at 800 x 600, I wanted to see how long it would take on high settings, and I also saved the IRR. map and LC map, so I could reuse it for my 4K render, which I did, and because of that, my 4K render only took 1 hr. 17 min.

 

The last pic is a piece of the 4K render to show how clean it is after using the 800 x 600 maps.

 

I'm going to go back and work on the MR scene, where I was making progress, thanx to Justin, I'll post something soon...

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Manta

 

Looking good. I really like the detail in the closeup.

 

There are a couple of things that you need to fix on your model. First is adding an autosmooth to the chair to get rid of the banding and the other is there are some objects, such as the metal ring on the glass table and the bedside table top, that have way too many segments. There may be more but these are making the scene heavier than needs be.

 

Once I get back into the office on Tuesday I will work up my version some more. This is a good one to play with.

 

JHV

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Well here I am with MR...

I finally got the displacement for the carpet working, looks pretty good...

 

but I'm having some issues with the DGS material on the metal surfaces reall grainy, I just want some blurry reflections, there aren't any quality settings for the material as far as I can find...

 

There is also something funky going on with the bottoms of the curtains ??

 

I would also like to soften up the shadows, they're raytrace, so I don't think I can do that ???

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