Blurry reflections, Maya, mental ray, etc.?

[deltacharlie]

:confused::confused::confused:

I've determined that I really need to do something like blurred reflections if I want my plane to look correct (simulating doped linen on WWI craft)...but I can't seem to figure out how to get anything that looks right in Maya. I see lots of examples for mental ray, but that's not a learning curve I want to tackle right now...but is it the only way?

Do people who use other packages have built-in blurred reflections, or what do you do?

I don't really want to create an environment map and blur it in photoshop, because then I'd basically have to do that for every scene separately...or am I wrong? Would it look fine regardless of the scene?

Help me, Milmesh, you're my only hope! ;)

~DC

[kevjon]

In max you can blur reflections with the fast adaptive antialiser when using the scanline renderer & raytrace materials.

or

You can use the mentral ray renderer and blur reflections using metal and glass lumes incorporated into max's standard materials

or
Use mental ray renderer and mental ray materials. MR materials usually have an option to blur reflections.

Do I use them ? Yep sure do.

I don't really see the point of blurring the environment map because that will reflect blurred but parts of the aircraft such as fuselage reflecting into a wing will be really sharp so that is why its important to use materials/shaders or a render engine that have blurring options so that both the environment map and self reflecting parts of the aircraft are all equally blurred.

[jiverson]

I don't know about Maya, but in C4D it gives the option to add dispersion to reflections. That helps break up the reflections so it doesn't look like your model was just dipped in clear coat gloss. I also use some fresnel in my reflection map to simulate how things are more reflective at higher viewing angles. I use standard reflection and not environment.

Does that help?

[deltacharlie]

Thanks...jiverson, the only place you can add dispersion to reflections is within the mental ray shaders in Maya.

Kev, I guess I was thinking about trying to include the struts in the env map...but when I actually consider that I realize it would be quite difficult to get it to look right if I did that...basically I'd have to make a bunch of different env maps for different surfaces.

The more I look into it, the more it seems that MR is the answer. I've started looking into it, but I haven't gotten the results I want yet...we'll see how it goes. I've had trouble with MR in the past so I avoided it but I think it's the only way to get the effects I need. I'm sure it won't kill me to learn anyway. :)

Thanks!

~DC

[kevjon]

Although I've never done it, another option might be to render out the reflection as a seperate pass and blur it in photoshop to suit your taste. That will avoid having to learn mental ray which will take some time away from modelling and texturing.

[deltacharlie]

:salute:

That's actually a great idea and I'm kicking myself for not thinking of that. I've done stuff like that for work-related projects and it worked well.

I still think it might be beneficial in the long run to learn MR, but if I get frustrated I'll try this. Thanks!! :D

~DC

[kevjon]

I've never been totally happy with way 3D max blurs reflections either, so I'll probably go the photoshop way as well which should give me a bit more contol of it.

[raf]

Not sure how bluring a reflection layer in photoshop would work. I can imagine some problems with edges and the fact that objets that are closer to the reflective surface should be less blured.

If you are already rendering in separate layer, why not render reflection in MR and have it blured straight away. That shouldn't be too difficult to set up even if you don't know your way around it.

P.S.
And yeah, max default scanline sucks bigtime for reflections, and for blured reflections it is pure disaster. I think some of my scenes, made year ago, would be still rendering if I used scanline renderer.

[kiwi123]

An other thing you might try is to add a tiny bump map to your surface. That's why reflections blur in real life, the surface isn't perfectly smooth. That's the way I used to do this in the past, but you probably need to render at a much higher res and scale down your render afterwards to make it smoother.

The only other thing I can add is that it's worth to learn a different renderer from maya's standard one. Maya's standard renderer is ok for simple stuff, but not great. Mental Ray or Renderman For Maya are far more advanced.

Both Modo and LW support blurry reflections out of the box as well. Strange that Maya doesnt actually...

[kevjon]

Not sure how bluring a reflection layer in photoshop would work. I can imagine some problems with edges and the fact that objets that are closer to the reflective surface should be less blured.

Yep good point.

If you are already rendering in separate layer, why not render reflection in MR and have it blured straight away. That shouldn't be too difficult to set up even if you don't know your way around it.

Trouble with MR if you just want to blur it very slightly it ends up very grainey. Seems to need lots of samples to make it smooth which also makes it very blurry.

[deltacharlie]

I'm not too worried about the edges, because the reflection layer bg will be alpha-masked out.

I think the best solution is probably to do both. :) I.e., man up and learn MR, but render the reflections on a separate layer and then I can mess with that in Photoshop. Kev is spot on (get it :p) about the graininess, but if I render in MR with default settings, it'll be less blurry closer to the surface, but I can blur the whole thing more. Actually I'm more interested in stretching the blur a bit vertically, which ought to be fine.

Now if I could just get my daughter to go to sleep earlier so I have some time to mess with it! :lol:

[raf]

Now if I could just get my daughter to go to sleep earlier so I have some time to mess with it! :lol:

You can try reading her some stuff from MR manual, that might help, :lol: plus you get to learn something about it.

Does MR in Maya have Arch&Design material? There you can get blurriness by reducing glossiness in reflection section, and stretch it with anisotropy. Newer versions of MR have additional options for fast interpolation of glossy reflections in Arch&Design mat (helps with that grain and its faster).

[Doan]

Hey Deltacharlie,

Just saw this thread. The easiest way to get blurry reflections in MR or maya software is to put a high frequency bump on your object. It can be very subtle and still provide the desired result. One of the few cases where the effect is achieved in the software just like it is in real life :)

[Xizor]

I believe from Maya7.0 and up there is a mental ray tab in the shader options that is added automatically when you turn on/enable the mental ray plugin. It willl give you 3 options
( scroll down the shader to see )

MiReflectionBlur - default is 0 , this number I believe is based on the angle of reflection, basically reflection rays (not fg rays) get shot into the scene and deviate within the range set by you resulting in a 'blurred' appearance e.g A value of zero is a perfect specular interaction or very close to ( with the dispersion and visual appearance of the material faked by a bump map), a value of 90 would be a perfectly diffuse reflection or refraction. In my renders for personal and work i usually use between 6-16 for the blur

Reflection Blur Limit - default is 1 , not exactly sure what this is i would guess this is how many times the reflection ray will bounce/scatter , leaving it at the default of 1 is usually good

Reflection Rays - Is the number of reflection rays to use for blurring. the number entered specifies the number of rays to use to sample the random deviation in the angle you have just set. The more rays you use the better the blurred result will be, setting this to a too low a number will give you artifacts at render time, Without question higher number of rays are required for more blurry reflections/refractions. You will have to have other sampling parameters also to help with this such as per-object samples ( done on a object per object basis ) and supersample which you can set in the MR Render Globals. If you change any of these 2 settings or both you can lower the number of rays without to much loss in quality and shave some render time too.

Thats if your using Maya, also you can also use the mia_envblur and have it connected to a mia_shader but i wont go into that cuase there is a 124page document on that shader here which explains it in detail http://www.mentalimages.com/2_1_8_documents/arch_and_design.pdf

[deltacharlie]

Doan: thanks! I actually gave that a quick whirl and was shocked to find that it worked! I might mess with that some more.

Xizor: I think someone else mentioned that there were reflection blurring params on Maya shaders with MR, but I couldn't find 'em. Maybe I was too tired that day or went a bit crazy..but I looked this morning, and it's there just as you said. Weird. Thanks for the info!

I now have a bunch of options to try...I just need time. Thanks all! :)

EDIT: raf, thanks for the tip on getting my daughter to sleep. :lol:

~DC