Mentalray current workflow sticky thread

Discussions about rendering in SOFTIMAGE©
Falam

Re: Mentalray current workflow sticky thread

Post by Falam » 20 Apr 2013, 05:36

Hold up the visibility switch in the mila_mixer node is strictly just that a visibility switch the material, far from what I want, inverting the alpha didn't solve the problem, rather as expected reversed the materials transparency. ~x(

Kzin
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Re: Mentalray current workflow sticky thread

Post by Kzin » 20 Apr 2013, 17:55

Falam wrote:Hold up the visibility switch in the mila_mixer node is strictly just that a visibility switch the material, far from what I want, inverting the alpha didn't solve the problem, rather as expected reversed the materials transparency. ~x(
the mixer is only that, a mix node. if you want the cutout opacity function, use the visibility option in mila_material. if you want simple transparency, use the mila_transparency node.

Falam

Re: Mentalray current workflow sticky thread

Post by Falam » 21 Apr 2013, 07:24

The image I'm using has an alpha channel. I've changed the weight of the shaders, hoping the image will show with the alpha. Plugging an image with an alpha in the 'tint' slot of any of the mila shaders doesn't work correctly, the image will only control the weight of the material based on the image, not what I want. If I use a Mix2 node it will break the physical accuracy of the mILA shaders. mILA transparency didn't solve my problem either, I add a layer, plugged my image with the alpha in the color port, used a picker node to extract the alpha for the weight of the layer, doesn't work.

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Daniel Brassard
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Re: Mentalray current workflow sticky thread

Post by Daniel Brassard » 23 Apr 2013, 14:09

I think we are deviating from the intent of this thread, the last few conversations should have been in the "New Mental Ray shader development thread.

http://www.si-community.com/community/v ... &start=120

Cheers!
$ifndef "Softimage"
set "Softimage" "true"
$endif

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gustavoeb
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Re: Mentalray current workflow sticky thread

Post by gustavoeb » 23 Apr 2013, 19:38

so, just playing with user_rect to get some screen grabs here...
testing it with light importance sampling on will actually result in a much poorer quality here, any one care to share their experiences?
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gustavoeb
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Re: Mentalray current workflow sticky thread

Post by gustavoeb » 23 Apr 2013, 20:41

some screengrabs up... will try to work more on this as the week progresses...

any thoughts are very welcome :D
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Kzin
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Re: Mentalray current workflow sticky thread

Post by Kzin » 23 Apr 2013, 21:15

dispmapping:
use "fine" displacement as default.
dont use "view dependent", its to unstable.
dont presubdivide your mesh for dispmap only, its not necessary (will increase the memory usage and also the preprocess time), reduce the lenght parameter instead
dont raise the max subdive parameter blindly, for example, if you use a low lenght parameter you can also use a lower max subdive normally
let the min subdiv value by 0

Fer
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Re: Mentalray current workflow sticky thread

Post by Fer » 23 Apr 2013, 22:07

gustavoeb wrote:so, just playing with user_rect to get some screen grabs here...
testing it with light importance sampling on will actually result in a much poorer quality here, any one care to share their experiences?
Light IS doesn't work with user shader and builtin, there already have there own IS built into theme. using IS with any lights result in more noise and bad render time for me, except object textured light. we should wait the new lights to see how IS is helpful.

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Re: Mentalray current workflow sticky thread

Post by Eugen » 28 Jan 2014, 17:04

Guys,
hope this is the right place to post.
Got a basic IBL problem here, which I thought this would be straightforward, but it ain't...
I like to use mental ray for this architectural job. Not VRay (because of a bug), not Redshift (need hair), not Arnold (not mine to use). Besides, I like EnhanceXSI.

So, the question is, what's the 'traditional' setup for image based lighting with final gather? Outdoor scene for now. Indoor later...

Basically, using a normal Environment shader and some HDR image works, but when I use a black image with just one very bright spot (sun) in it, I just get a few white splotches across the scene. Cranking up the 'numer of rays' parameter does not really help.
Looks like there's no real importance sampling going on for the env. image, is there? Is mray really so far behind here? Any alternative shaders?

I tested the user_ibl area light shader, but do not get noise free results. Also, is it usable in conjunction with final gather?

Thanks for a quick answer before I have to dig through many pages of info...
Best,
Eugen

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rray
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Re: Mentalray current workflow sticky thread

Post by rray » 28 Jan 2014, 17:14

If you're not doing animation the environment lighting mode is really good. It uses the current environment to light the scene. It basically simulates the first final gathering bounce, but works much faster and has a really good quality. If you use final gathering in addition the first bounce is ignored and you can use very low fg quality settings.

You can use the ctrl_ghost_settings geoshader to activate it

For animation there's the problem that the geoshaders are not updating between frame changes. Stills you can just render twice or refresh the render region.
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

Eugen
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Re: Mentalray current workflow sticky thread

Post by Eugen » 28 Jan 2014, 17:37

Hi rray, thanks!!
Can you give me a little kick in the butt:
- so, the 'native (builtin) IBL' is stable and everything? Cool... amazing that this stuff is still unexposed...
- but where to get the lates ctrl_ghost shader? On rray.de/xsi it says, could be outdated.
- what's the string option then to activate builtin_IBL?

I'm just rendering stills for now, btw.

Cheers!
Eugen

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rray
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Re: Mentalray current workflow sticky thread

Post by rray » 28 Jan 2014, 18:36

- so, the 'native (builtin) IBL' is stable and everything? Cool... amazing that this stuff is still unexposed...

seems very stable. Even works for skin shader, hair etc. You can even render like 100.000 hairs quite fast.

- but where to get the lates ctrl_ghost shader? On rray.de/xsi it says, could be outdated.

That one was working for me. That message is just a reminder there could be a newer version, but for most plugins there isn't.

- what's the string option then to activate builtin_IBL?

you can find them here
https://support.caustic.com/forum/tips- ... talray-ibl
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

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Daniel Brassard
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Re: Mentalray current workflow sticky thread

Post by Daniel Brassard » 28 Jan 2014, 18:45

String option plugin for Softimage here BTW:

http://www.si-community.com/community/v ... =27&t=3312
$ifndef "Softimage"
set "Softimage" "true"
$endif

Eugen
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Re: Mentalray current workflow sticky thread

Post by Eugen » 28 Jan 2014, 19:49

Cool, thank you, guys!

Just rendering black, though. Anything else to think of? Can't see the new options in the render log...
- The environment image stays connected to an Environment shader, correct?
- Do I need the quotes "" for the option's names?
- Does FG has to be turned on? No, because native IBL is using primary rays, right?

Thanks again,
Eugen
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rray
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Re: Mentalray current workflow sticky thread

Post by rray » 28 Jan 2014, 19:59

You have to refresh the render region, it's that refresh bug probably. I hope it gets fixed in some future.
Fg doesn't need to be on, you're right those are primary rays.
No quotes needed : )
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

Eugen
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Re: Mentalray current workflow sticky thread

Post by Eugen » 28 Jan 2014, 20:11

I refreshed it, but no luck...
What's suspicious is that the native_ibl options are not logged among the other render options.

Don't want to ask too much, but do you have a working scene, by any chance...?
Thanks!!
Eugen