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Learning redshift

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Hey

For all who have gone through this, how long does it take to get up to speed with redshift? Is it a smooth transition, or are there a bunch of gotchas that need to be learned? 

I've used a bunch of offline renderers, but the GPU world is new to me :).

M

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Main difference in my opinion is vastly reduced set of vops  compared to mantra and very rudimentary volume shader. Other than that it is a lot like mantra except it is great deal faster.


It is very prone to crashing if you don't turn off IPR while making changes to geometry while just tweaking shaders is fine.

Regarding the amount of geometry/textures you can throw pretty much anything at it and it will render just fine. I recently finished project with loads of heavy meshes made from nurbs models and around 50 materials from megascans (mostly 8k) I thought I will downscale at some point but never actually had a need to.

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Many of the gotchas, I experienced when I first started using Redshift have been ironed out with the continued development of the plug-in. Mainly an object that does not have the ObjParms applied to it can cause some problems. If they are not present, attributes will not be automatically forwarded to the material section. This can happen if you open old files and try to adapt them to Redshift. However, newly created objects do have ObjParms added by default, so just double check that if things seem like they are not working correctly.

Another gotcha that I still run into is not experiencing glow from material emission on surrounding objects. This is because GI is turned off by default. You need to turn on one of the methods (typically Brute Force) to get some kind of emission bounce. But this is often the case with other render systems as well.

Balancing density and temperature values in the volume shader can take some time too. I have adopted the workflow where I don't push density at all in the guides, and this helps get a better 1:1 match from viewport to render. Push your density values at the attribute or scale level, instead of guides.

There is the 16 bounce limit on reflections as well. If you need more than that, you have to leverage the sprite cutout node instead of just relying on the standard material.

Meshlights don't inherit v@Cd from points so you have to bake maps for multi-colored meshlights, but single colored meshlights work fine.

Edited by Atom
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can you please clarify on how to add objparms to objects?

I built a complex scene in mantra and I just downloaded redshift but none of the materials are rendering. I created the materials in the material palette before downloading redshift. what can I do?

Edited by elkhash

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You have a shelf tool, where you can add the obj properties, and btw now as soon as you add a geo it gets added by default. 

houdini_2019-02-21_08-54-04.png

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thanks hernan for your prompt reply. i tried adding the objParms to all the objects i have in my scene. I also changed the type of my materials to Redshift materials instead of principle shader, but none of my materials work.

alot of the objects are imported FBXs with materials.

Please see below screenshot of render in mantra and redshift. What can i do to make my materials visible?

thanks in advance!

 

Edited by elkhash

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I wrote a couple of helper script which build redshift materials from .MLT files and from imported FBX material network.

They might help, you can check them out here.

 

 

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dude!! cant tell you how grateful I am. it works perfectly. been trying to figure this out forever. huge thanks !!!!!!!!!!!

one last question, i have several objects to apply this script to, would i have to create individual scripts for each object?

also, my skylight renders out totally different colors in redshift than it does in mantra, is this normal? 

thanks so much

 

Edited by elkhash

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I placed my code in a shelf tool button and then just setup a crude variable based switch to point to the models I was processing.

Something like this...

n = 2
if n==0:
    texture_path = '/media/banedesh/Storage/Documents/Models/Blendswap/cc0_Destruction_Assets/Building_Budova~/01'
    file_name = '/media/banedesh/Storage/Documents/Models/Blendswap/cc0_Destruction_Assets/Building_Budova~/01/21_budova.mtl'
if n==1:
    texture_path = '/media/banedesh/Storage/Documents/Models/Blendswap/cc0_Destruction_Assets/Colosseums/Colosseum4'
    file_name = '/media/banedesh/Storage/Documents/Models/Blendswap/cc0_Destruction_Assets/Colosseums/Colosseum4/Colosseum.mtl'
if n==2:
    texture_path = '/media/banedesh/Storage/Documents/Models/Blendswap/cc0_Destruction_Assets/Fancy_Architecture/002_Sanpietro'
    file_name = '/media/banedesh/Storage/Documents/Models/Blendswap/cc0_Destruction_Assets/Fancy_Architecture/002_Sanpietro/sanpietro.mtl'

The dome light should work, is it a gamma issue or a color shift?
By default, the MPlay render window that pops up has the wrong gamma, it defaults to 2.2 and it should be 1.0. I have to manually change that all the time. But if you poke around in the Redshift render ROP you can specify what gamma is sent to the MPlay window.

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thanks for your reply, 

i think its a color shift issue, please see the difference in the attachments. I've adjusted the gamma to 1.0 in the render shift rop as you suggested.

im also still trying to figure out the colors - any advice on that would also be appreciated. second image is redshift, last image attached is a render in mantra with vr camera. 

capture7.1.JPG

Capture7.JPG

screenshot.JPG

Edited by elkhash

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It looks correct to me, have you tried selecting one of the Global Illumination engines with Redshift? By default I think they are turned off. Try choosing Brute Force for both drop downs.

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the third image I attached in the previous post is a mantra render. which is what I want the scene to render as. I couldn't render it with mantra as it was taking a crazy amount of time just to render that one frame.

the image before that is a redshift render using the exact same environment light and skylight. the materials aren't showing up even though I've created new redshift materials and the colours of the skylight are off. (blue looks darker, grey looks brown) and the overall lights of the scene are off. 

I turned on brute force for both and followed these directions for setting up the GI (http://www.haruvfx.com/post/20) it still looks like the second image. 

anything else I can try?

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