Have you ever experienced, all of a sudden, Max to stop rendering furry objects? No matter what you do, no matter how hard you try, no nothing, it just won’t! Also, another great thing is the shading of the fur. You can setup fancy lights, fancy shadows, nice speculars etc… and then you realise your fur is totally overbrightened from… hell I know?!
I really envy the 3Delight implementation of Shave and a Haircut’s hair/fur geometry and the shaders, they work beautifully and exactly you want (obviously, you wrote the shader so if it wasn’t working the way you wanted, it’d be a huge bug).
Anyways, 3ds Max’s hair and fur is really, really, bad. It’s not even good for low-budget, low-end productions, it’s completely useless. The only thing that might have a chance of pushing it a bit farther was mrPrim rendering. But then again, mental ray is also such a terrible renderer (at least in 3ds Max) and then again, hair and fur is so buggy in Max it isn’t even worth mentioning.
Man I hope Autodesk does something about this issue soon, or everyone will have to move to proprietary solutions for hair and fur stuff. As they’ve been doing forever anyways… *sigh*
I knew I’d not only get an answer but a complete solution to my black lines problem with mental ray, when I ask no other than the big Mr. Zap himself!
He pointed me to a discussion of this issue in mental ray, which turned out to be a NaN issue in floating point value pixels. Thankfully, there also was a solution to this problem, which was to use, one of mr’s great features and advantages (custom shaders), a Lens shader written by David Landier.
This, D3DBlackSpotsRemover lens shader does a simple math to check for a value of each pixel and fixes it if it finds a deviation.
Thankfully, this bug has been fixed in 3ds Max 2010, but I’m yet to test it out to see for myself and seems to be working just fine, which is awesome news! Anyways, big, big thank you to Master Zap and David Landier of course, they’re the men when it comes to mental ray!
Edit: Sorry for not posting the direct link to the shader, here it is over at David’s site.
The site is a bit confusing, so I took the liberty and mirrored the shader on my server, without permission however, so if you read this, David, and don’t want me to mirror your shader, let me know and I’ll take it down immediately.
Here’s the mirror: DL3D_BlackSpotsRemover
And here we go again.
This is another of those errors I can’t seem to get rid off. It’s not as severe as in the previous example, but still annoying as hell.
The problem is that mental ray renders pure black pixels or lines, completely randomly. It doesn’t write them in the alpha, though, but writes them in the beauty pass. Sure enough, with motion blur and everything, you can pretty much get rid of these bugs, but sometimes the errors are much larger than that and become extremely difficult to get rid of. Like in here:
Another of those errors… I hate mental ray.
As a follow up to my previous rant about mental ray in 3ds Max, here’s another beautiful example of its “usefullnes” in production.
I’ve been working on some “fur” shots on the latest project I’m about to finish in about two weeks from now and I haven’t berated so much in a long time! Here’s a test shot of a furry ball very roughly put together just to demonstrate the point:
and here is the problem seen on the very same render’s alpha channel:
this is what happens when you superimpose the render over an arbitrary background:
Isn’t it wonderful?!
I remember this bug from the old 3ds Max 8 days. Unfortunately, it’s the year 2009 and this was rendered in 3ds Max 2009 (will test 3ds Max 2010 asap) with mrPrim set as the Hair Rendering method. Now this can be avoided by using a different Ray Sampler the Fast Rasterizer, however, this option yields even less predictable and reliable results. Although the hair alpha channel gets rendered correcty, I often get artifacts in the render buffers in forms of random black pixels or random black lines (not affecting the alpha though), but some times the rendering simply gets stuck forever never actually finishing the current frame, which is very bad!
So, please, those of you who use mental ray daily, educate me, I can’t believe this would just slip out in this form as a “final and ready for production” product! I refuse to believe so!
Having to work with mental ray on the current project has been the most painful experience I’ve had in a long time. The countless crashes, low quality and constant “bugs” during the rendering almost drove me mad! mental ray is a strange renderer. It has some amazing features, but at the same time it lacks so much functionality and then there are the bugs (random black pixels or random black lines over your renders, unpredictable crashes etc…). I really hate it and can’t wait for this project to come to an end and I’ll be able to go back to my beloved finalRender Stage-1 and Stage-2 (for Maya).
A friend of mine asked me how I’d go about rigging a wheel so that it spins no matter which direction it travels and stick to a ground as well. At first I thought this’d be a piece of cake as all I really needed was a direction vector and its magnitude to add to the rotation of the wheel. Well, the solution turned out NOT to be that simple in the end.
(the video lags a bit, but the entire rig is actually faster than real-time)
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