Iray Canvasses and tone mapping help
Oso3D
Posts: 15,085
in The Commons
I'm attempting to break into the funky world of Iray Canvasses, now that I have Photoshop.
After Tobor's tip, I tried shutting off Tone Mapping and ... wow. End up with either flat white or wildly weird lighting effects. (Is that normal and massagable?)
I then tried turning off burn by components and burn highlights and crush blacks. Now I'm seeing lots of speckling and convergence stuck at 0.00%.
Advice?
Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2025 Daz Productions Inc. All Rights Reserved.
Comments
You can leave the tone mapping On it oes not affext the exr
It only effects the JPG/PNG
The exr will always look White or Black or strange until you did the Tonemapping in PS
Not sure if you're aware, when the render is done, the EXR canvas files are placed in folders in your render output directory. Use those, not the image in the render window. The render window images will still be only 8-bit.
When you bring them into Photoshop, you have to tone map them. Image->Adjustments->HDR Toning.
There are a number of threads here that talk about how to do use these. User Esemwy has been involved in many of them. Do a search on his user name for his poists. Here's one, as an example:
http://www.daz3d.com/forums/discussion/62101/relighting-with-iray-canvases/p1
Aaaah. I knew about the canvass folder, but for some reason I assumed the main window had some impact on it. Duh. Thanks!
(I'm also THRILLED to finally have access to the distance/depth canvasses, since I was previously resorting to doing additional renders in 3dl with a depth camera.)
Also don't forget there are many other uses for canvases beyond external tone map manipulation, or fiddling with light paths for composition. It can be much simpler, like a series of node-based Beauty renders. As shown in this example, you can render a general background body, and then render separate parts that you can easily overlay in your graphics program. You can do this with clothes, hair, props, whatever. Node rendering requires selection of separate objects; won't work with bones or just surfaces. There are other methods for doing that, like rendering to a MaterialID output, and then use that to produce image masks in Photoshop.
Yeah, I've been thinking of playing with that at some point. Not entirely sure, yet, what I'll do with it, but I can see some purposes.
Do node renders work with transparency? MaterialID doesn't seem to.
Leaving the tone mapper on for EXR canvas could result in non-linear output, as per this post
http://blog.irayrender.com/post/76948894710/compositing-with-light-path-expressions
Note there's a follow on article (can't find the link right now) that updates this post. This post was made before Iray provided a tone mapping on/off control. nVidia followed up on requests and specifically added it, so it would not be necessary to make these other manual adjustments. They also added Nominal Luminance to provide manual hinting for the firefly and noise filters, which are normally enabled by the internal tone mapper.
Yesm as long as you check off the Alpha option.
Don't need to. You use these to create a mask in Photoshop (or GIMP or whatever), based on color selection. The color can act as either a positive or negative mask, depending on if you invert it.
I could not replicate this.
Just Leave Tonemapping on and add a Beauty Canvas and render.
The shut Tonmapping off and rerender
I could not detect any differnces in the exrs.
The only difference is that in the first render you get an usable JPG/PNG output and see something meaningful in the Render Window,,,,
Just out of interest were there any improvements from 4.8 to 4.9 with the Canvas stuff ?