Maya 8.5 Sun/Sky Rendering Bad

#121

Could anybody post about the difference in using the mia_exposure or the ctrl_buffers as a tone mapper? Is there anyone working better than the other?

I have also read that the gamma correction works better in post so we should disconnect the tone mappers before rendering and apply the good gamma in the 32 bit outputed images. So which would be the best way for applying that correction in post. Probably mia exposure simple is a simple gamma correction but, what about if using a tonemapper (ctrl_buffer)? I guess proper gamma correction and tone mapping are based in different computations, so how do you guys deal with this two issues (gamma and tonemapping) in post?

Thanks in advance

Edu

#122

How about specular Color, Ambient Color and Transperancies? Do I need to connect a gamma (0.454) node to these as well? I also having trouble with washed out shaders with transperancies, for some reason the transperancies are too bright when using gamma(0.454).
And is there someone who can make a script that automaticly places a gamma(0.454) node between your file texture and the color input?

#123

Can ppl complaining about Mental Rays renders please read the help files that come with Maya and read how to use all these new features. Once you know how to use them they are very good! I’m sick of hearing ppl saying that they are not getting the look they want all coz they have NO idea what they are doing.

Once you know how to use the program you should be able to achieve Maxwell like looks in less then half the render time.
Here is a quick test I did http://forum.lamrug.org/viewtopic.php?t=1093

Digital Tutors have some excellent training videos for Mental Ray, please have a look. Also it wouldn’t hurt to learn a bit about how light and optics work in the real world.

Iv tried using Final render, Vray, Renderman, Maxwell & turtle and though every renderer has its strong point I found Mental Ray to be the best overall. I must admit it dose take longer to learn then most, but its well worth it.
#124

Now this might be off topic, but it’s a really strange artifact that I get when using fractals node as clouds with e sky shader

I was trying to get that Power Animator old sky system look/feel

The artifacts that you see there are NOT shadow (or at least what I discovered thought the testing)

[size=2]Changing the object poly count will affect the look of the artifacts, as if it’s the way FG calculate the neighboring pixels
[/size]

#125

Yes dude! I have similar problems when I try to map clouds to the haze parameter of the physical Sky.

I post an image to find any answers.

#126

Maybe I’m wrong, but in maya 8.5 the new physical_sun&sky, differently than the old one (maya 8.0), the Haze of the sky is also mapped to the haze of the sun, so you have the same ‘effect’ in the two elements (sun&sky): that should be the cause…you can try to break the haze connection between sun&sky, probably it’s wrong but maybe it works.

#127

:thumbsup: Ok dude!!!

That´s the answer, it´s works perfectly.

thanks a lot

#128

Hi, just moved to Maya 8.5, finally. I put together a little mr phenomenon based on mia_material to automatically remove gamma on input colors. Basically what I had done for Maya 7.

mia_material_rg (remove gamma) will automatically “ungamma” input colors. Gamma correction (default = 1/2.2) is adjustable, see near bottom of attributes. Color swatches and viewport colors will look normal (not “ungammaed”), the mr rendered “Sample” preview and the render itself will have input colors gamma corrected. Your render should have gamma applied (typically 2.2). Adding Physical Sun and Sky by default adds a 2.2 gamma correction to the render using mia_exposure_simple. Note that you can disable the gamma correction by setting it to 1 1 1 (will behave like regular mia_material); for example, you could set it to 1 while editing the “Sample” preview, and set it back to 0.454 for rendering.

This is a simple phenomenon but I thought I’d share in case anyone else finds it useful. Sorry for the poor packaging, I’m no shader expert, if you are not using a default Windows Maya 8.5 installation you will have to edit the includes in the .mi file and install manually. Once installed, a new mr material will appear called “mia_material_rg”, it’s exactly like mia_material except it has built in gamma correction for all input colors (not bump, transparency, etc.). This does not change or affect the original mia_material.

(Edit: updated mentalrayCustomNodeClass.mel to Maya8.5 SP1’s)

#129

Well, well, well this sounds great!!!
We might just “love” you sphere(heart) :slight_smile:
Now… I have a little problem… Most of the time I use maya on osX, so, could you maybe
explain what will I need to modify exactly and where will I need to put it in osX ???
Thanks a bunch!

#130

hi q_vazk, if you look at the included Readme.txt it’ll indicate where to copy the files. For OS X the only thing you’ll need to edit is the two $include lines at the top of the mia_material_rg.mi file with the correct full paths for your system. I wish I didn’t need to have full paths in the .mi file, but it didn’t work without them. The phenomenon must ensure both architectural.mi and mayabase.mi are loaded first, otherwise it won’t work, thus the includes.

#131

Just tried it. Seems to work pretty well. Only thing I noticed was that the presets are no longer available. Anyone else get this problem? I decided to un-install it and use the normal mia_material so that I can use the presets and now the default mia_material is missing. Any ideas?

#132

Hi Phainey, mia_material_rg is a different material; you can copy all of your existing mia_material presets to mia_material_rg by simply copying the entire directory: “[installed path]\Maya8.5\presets\attrPresets\mia_material” to “[installed path]\Maya8.5\presets\attrPresets\mia_material_rg”. (Oops, forgot to add that after copying, you then need to edit each preset file and change one line near the top: startAttrPreset( “mia_material” ); change it to: startAttrPreset( “mia_material_rg” ):wink:

When you removed it, if you deleted the file “mentalrayCustomNodeClass.mel” from your “[installed path]\Maya8.5\scripts\others” directory, that’s probably your problem. It’s a required Maya file, leave it there or restore the original (if you used Install.bat, go to the scripts\others directory and rename mentalrayCustomNodeClass.mel.ORIG to mentalrayCustomNodeClass.mel).

#133

Hi Sphere thaks for the info on the presets. I tried restoring the mentalrayCustomNodeClass.mel.ORIG back to mentalrayCustomNodeClass.mel but that didn’t seem to work. I’m still missing the mia_material. By the way, I did use the install.bat. Any other ideas?

Thanks,

#134

phainey, sorry, I can’t guess what you did. Installing mia_material_rg does not affect existing shaders, like mia_material. The Install.bat I included is extremely simple, it basically does what the Readme.txt explains. I did not provide an un-install, so I guess whatever you did when you “un-installed” it, you might have deleted things you shouldn’t have.

#135

No problem Sphere. I figured out what went wrong. I had copied my scripts from maya 7 over to maya 8.5 and forgot that I had Yashu’s PhysEnv scripts in Maya 7. Once I removed them, your stuff and the default mia_material are back to normal.

Thanks,

#136

Okay, I’ve read this thread but I’m still having problems in trying to render out with the tonemapper. octane52’s image is a perfect example in what I’m trying to achieve, just a nice clean, contrast and nicely saturated image. Instead I end up with all these:


Either really dark or washed out or looking really compressed. I’ve played around with a lot of different settings (using the preview trick) but it always looks wrong no matter what.

All textures and swatches have a .454 gamma node applied to them and Gamma is at 2.2.

I’m able to get an acceptable result in just deleting the tonemapper altogether and doing the correction in post but that’s a disjointed workflow. Is there an easier way to use the tonemapper are there alternatives? Are the defaults for the tonemapper usually acceptable or is there always a lot of tweaking involved?

Thanks.

#137

Difficult to tell from those icons, but it looks like sun and shadow. You can’t take a real photograph with the full sun (no clouds) and full shadow being both properly exposed at the same time without tricks. If the full sun part is properly exposed then the shadow is dark; or the shadow is properly exposed and the full sun part is blown out, this is normal in photography; and it looks like what you are getting. But you could try increasing FG secondary bounces to attempt to get more light in the shade.

Here are some quick google images, exposure is set for the full sun area, the shade is black:

#138

Thanks Sphere, I know that’s normal but it’s not exactly the problem I was having. Those pictures aren’t the best examples.

Basically I’m new to this kind of workflow and I’m using Yashu’s port with Maya 8.0. I’m just not sure of the right approach in using the tonemapper because right now I’m getting ugly results.

My questions are:

  • Is it better to go with the tonemappers default settings and adjust the shaders, or is it better to leave the shaders alone and adjust the tonemappers settings?

  • Does the tonemapper’s settings always differ vastly from project to project? I’ve tried using other settings such as the picture in this thread(last post) but when I use those settings my renders turn out black.

  • Finally, when batch rendering out as a 32bit exr is it better to unplug the tonemapper and keep mr’s framebuffer gamma at 1? If this is the case, then the tonemapper is basically just used for the renders internally in Maya so you can get a preview of what you’re render will look like after it’s adjusted in comp?

I’m used to and I’m just trying to get a handle on how to correctly use it, that’s all.

#139

Well I can’t give you definitive answers, but I remember on the Maxwell forums they very strongly recommended to always leave the tonemapping to the default (with gamma 2.2) if you wanted correct results. It makes sense as digital cameras today use a gamma of 2.2, so if you want photo quality results… But a strong case to use 2.2 is that the colors (swatches), images and photos you use as materials already have a gamma of 2.2, this is why you need to “ungamma” them with the reverse 1/2.2 to make them linear if you want to use them as textures; if you ungamma them or gamma the results with different value, your colors will not be true. Also, the colors need to be realistic, i.e. a diffuse 100% color is not realistic, or a material that will add up to more than 1, or produce fake highlights, is wrong. Tonemapping should really only address light, not your shaders once they are corrected to linear color space and physically realistic. What kind of light you use is very important. If you look at Zap’s contribution on page 3 he writes about how typical Maya lighting is wrong (i.e. no/wrong decay). This is why I only use physical light and/or physical sun & sky with tonemapping. Actually, he writes about the entire workflow being wrong, so I also stick to mia_material (actually, mia_material_rg ;)) to avoid old style shaders that probably produce wrong results.

#140

Aha! Problem solved!

Basically I was having a lot of trouble with washed out things happening with the tonemapper on Maya 8.0 (Yashu’s port). However, I received my upgrade to Maya 8.5 today and it seems like the officially bundled tonemapper has changed quite a bit because the pedestal and gain work differently to the port…everything is working great now.