Help, I'm Mentally Challenged

#1

Here’s a quickie, and please send me to another thread if this is a repeat. Does anybody have a catalog of recommended settings for Mental Ray scenes? I’ve had rotten luck applying what I learned (the hard way) in one scene to another. When I throw the same settings at another scene, it blows up. It could just be a big table, and an entry would be something like:

Description: Architecture Interior
Scale: 20’x30’x10’
Lighting: 2 MR Areas at 1000cd each
Textures: Max Textures with Bump, some reflective
GI: 250 photons/sample, Trace 32/16/16
FG: 500 samples, no radius, Trace 2/1/1
Exposure: Logarithmic…

The problem is, when I set up a scene, I don’t know where to start, since there are so many cryptic settings. I end up changing 10 things at once, and the scene blows up a different way. Is there a good “tweaking order” - an order of settings you can go through to get incrementally better results? When you set up MR, what “generic” settings do you start with, and what’s the flow from there?

If you all have scenes that work, you can post the settings and I will catalog them in a big table. You can also send me the actual scene and I will pick it apart and add it. I just want a good cross section of MR scenes that have WORKED.

If I get some good responses, I’ll put it on the web in a way that’s accessible to everybody.

#2

Take a look at jeff pattons site.
http://www.jeffpatton.net/
He does great work with Mental Ray. It might be able to explane some stuff.

#3

You might get better results posting your scene at letting us rip it apart.

-S

#4

Okay, rip away at this one. I’ve got a fairly complex architectural scene that goes haywire when I try to apply GI. I get holes in my scene, like Bugs Bunny would escape into. It seems to have something to do with FG and my materials. With GI on and FG off, they don’t appear. With material override on, they don’t appear. When I try to render the scene normally, i get swiss cheese. I’ve tried a bunch of FG settings-- radius, tons of samples, etc., but they only make the holes shuffle around and change size.
I’ve got one big spotlight acting as the sun, and a skylight. If you all have any advice, please let me have it.
http://www.visioncompanydesign.com/churchwithholes.jpg

#5

I mean your max file, or a dumbed down version with the same settings and problems.

-S

#6

Hehehe, funny stuff…

By chance are you using architectural materials (mainly Arch. glass)?

#7

oh man, that sucks. You get the same problem in maya when you don’t use the proper mental ray lights. That won’t have anything to do with your settings. Mental Ray doesn’t like something in your scene. You just have to figure out what that is.

Try this…
Delete all your lights. Create one light you think shouldn’t cause a problem. Don’t let it cast shadows or do anything special. If you don’t get those stupid black dots (notice there are also holes in your alpha) then add one thing at a time to figure out what was causing it.
Are you trying to use a volume effect? Those are really touchy. If so, remove that and see what happens.

#8

Hey Guys,
I had been thinking about buying FinalRender,because Mental Ray charged a load of cash just for nodes. Obviously that’s changed now, so I’m wondering if it’s still worth it to buy another renderer. I know GI is faster/easier in anything BUT Mental Ray, but is it worth the money for the added speed/features exclusive to FR or Brazil?
My thinking is, if I build another computer as a render node, and FG can do things twice as fast, it’s worth it, since I’d be effectively doubling my hardware investment. Any thoughts on this?
P.S. What’s your ideal render box? I’m trying to optimize cost vs performance in raw rendering power.

#9

I have had those black spots on my renderings before. Usually what causes it is impropperly mapped objects. Or, to be more specific, objects that aren’t UVW mapped at all. Check to make sure every object that needs a UVW map has one.

Good Luck

Jon

#10

Problem: Black spots appear in Mental Ray renderings.

Reason: Final Gather does not work with Multi/sub materials with Raytrace reflections that are “FACETED”.

Solution: Turn “FACETED” OFF.

See 3DS MAX files attached.

http://www.3darchitecture.net/samples/Mental_Ray_BLACK_SPOTS_SOLUTION.zip

http://www.3darchitecture.net/samples/Mental_Ray_Simple_Test_(BLACK_SPOTS).jpg

http://www.3darchitecture.net/samples/Mental_Ray_Simple_Test_(NO_BLACK_SPOTS).jpg

Kenneth Loyd
3DArchitecture

#11

Man, you had to have done some serious voodoo to have figured that one out. Thanks a bunch. Mental Ray is so odd it takes a worldwide forum to figure it out, because getting the right answer involves blindly fiddling with a million options - hopefully without making matters worse.
I’ve gotten to the point where “jumping up and down on one leg while rendering” makes as much sense as anything else. And I still can’t give a coherent answer when someone asks, “What the crap is final gather?”
I’m still debating wheter Final Render Stage 1 would give me $800 worth of SIMPLICITY, not to mention performance.

#12

Check out the Cebas forums, lurk awhile, but pay attention to the FR-ST2 for cinema forum - it’s what’s in the pipe for MAX too… The shader nodes can be confusing but powerful, flexible, and you can create a library of setups… MTD is 50x faster (at least) than current Max FRST1…

#13

We bought this because a client of ours had it and we wanted to use their files. BIG waste of time. It cause max to crash Alot more often and the renderings were just Way to long for the quality that we wanted.
MR can be alot faster, but you still only get 8 nodes.

If you want a good price and a good product, then Vray. It’s cheaper and the learning curve is easier.

If you want easy to learn then that’s what I would suggest. They give you some straight forward setups to show you how to “properly” do animations, set up still renders, walkthroughs, and a few other things. Pretty good. It’s an online help file, but at least it’s updated often.

Final render’s help file is old, obviously doesn’t get updated, and the tutorials kinda stink.
I like MR because of it’s power and you can make just about anything you want (in maya, lol. Not as good implimentation in max)

#14

[quote="
I like MR because of it’s power and you can make just about anything you want (
in maya, lol. Not as good implimentation in max)
[/quote]

Well, that’s kind-of my point. That’s why FR isn’t a bad choice. Max crashes without FR’s influence in my experience. Maya hardly even crashes, so why isn’t everybody using Maya?

#15

yep, this happenned to me some times and i never really remember the right reason for each problem.
however, I love you peakyfreak , you solved my problem, i changed basic object with a metal shader , using Mr and Max, to a basic object with a standard + bump + raytrace reflection material , nothing special expect that my security swivel didn’t had uvw mapping . to be more accurate , i was try to get brushed metal with a bump map that had 0,0 and 1,0 for UVw tile so, i can’t imagine that Mr didn’t like this…

THANKS THANKS THANKS , now it’s beautifull ( not at all , but it will be enough for this week , i’m in holydays now, wauouooouu)

Mental ray 1
BLack holes 0

Tahnks
The chok -chocot

#16

i have to take more time next time…

#17

I dunno man… I’m pretty sure the ratio for me has had maya crash way more often while using it than with max. :slight_smile: But that’s probably just me.

#18

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