Canvases and post processing
mike9
Posts: 69
in The Commons
For iray under advanced settings there is a list of canvas types available:
How can they be used in post processing? The only information I found is about the lighting group here: http://www.daz3d.com/forums/discussion/62101/relighting-with-iray-canvases/p1 and beauty is obvious but what about the other ones?
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So the most basic is to create a Beauty Canvas.
You will get a 32 bit hdr file in exr createad additionaly to your picture.
You can load this into Photoshop and Tonemap there manualy when changing it to 8 bit.
You get much better results in most cases, so it is often worth the effort.
The others I'm still fiddeling around with so no really good tips yet.
Going to creat a Video Tutorial when I have more experience with them.
Here's another use of working with canvases:
http://www.daz3d.com/forums/discussion/comment/1035746/#Comment_1035746
Not sure what you are doing that results in 8 bit for you, Renomista. Mine remain 32 bit exrs.
SnowSultan did a tutorial using canvasses.
http://dazstudio-iray.deviantart.com/art/Iray-Canvas-Tutorial-565641976
Yes it does when I use the HDR Toning Correction,
But when i want to save it later as JPG/png Using Export i get other results as I see on the screen.
To save as Jpg it as I see it to screen i need to convert it to 8-Bit first. And here i have to apply HDR-Tone Mapping (again) and doing this twice leads to strange results.
But maybe I'm missing something
The most basic use of canvases is to stick with Beauty renders, and select scene elements to render using the nodes feature. Nodes correspond to complete objects (not bones of objects), and when rendered, will show only that portion not blocked by other objects.
You could use the feature, for example, to render different clothes on a figure. The clothing and figure maintain shadow features, and are easily comped together in a graphics program. Parts of the clothes not visible (the back side, for instance) are simply not rendered. This makes the process much more useful than if simply showing or hiding objects, and rendering them separately.
This process use does not require EXRs, but it does require that you use the alpha mask so you can more easily combine the images. Save as a TIF or PNG to retain the alpha channel.
I love the MaterialID Canvas - invaluable for creating quick masks of skin, hair, etc. Careful with skill caps on hair - I give it the same mat id as skin, but the rest of the hair a different one.
I have been deleting the exr files always as in the image editor it was only black & white. Dang.
Thank you I was considering to redo one of my renders for some camera blur but compared to 30 hours render time this looks way better. I'm not sure why there is only little information/talk about this as the canvases seem to be very usefull.
Hmmm. Ok, so who else is using canvases to do they're renders?
I went over the documentation center at daz for canvas information, but it seems a wee bit lacking:
http://docs.daz3d.com/doku.php/public/software/dazstudio/4/referenceguide/interface/panes/render_settings/engine/nvidia_iray/start#canvases_page
The entire 'Canvases' section is void of information.
Has anyone found further information on Canvases? The short videos I have seen on YouTube don't mention anything about using an HDRI for lighting the scene, just how to setup seperate canvases for each light in the scene. Doesn't help when using an HDRI for lighting though.
In my scene I have a car and one G3F character. Lighting the scene with an HDRI. I could setup a single light in the scene, but it won't make the HDRI show up, and if there is no 'Light.Group' then there is no way of lighting the scene subjects.
I have tried using the 'Environment', and 'LPE' canvases, but the render comes out blank in both attempts.
Also, I've added a skydome into the scene, then under canvases I set a canvas as 'Environment.Light.Group' with the Skydome selected as a node. BUT then the scene subjects show up as completely black, and where a HDRI should be is transparent.
Using the 'Environment Tab' (NOT in the render settings) to setup a background warps the HDRI in the preview, so I didn't even bother trying a render using it as a 'Environment.Light' canvas.
At page 14 of her art thread, @deathbycanon explains her process using canvases and also links her "how to" video.
I just had to go find the thread and the post. It's well worth reading most of the page, but you'll find the post where deathbycanon links to her video here.
I've also got some posts in my Art Studio thread, that cover the various types of canvases and how they can be used in post-processing.
This is probably the best single video for the wonderful many uses of canvases that I have come across:
He is demonstrating using vRay exr files and editing in Photoshop but it is the same principle, just have different names for the canvases than what vRay has is all.
If you are not used to using photoshops more advanced features then it may seem a bit overwhelming but it shows the power of what canvases can allow you to accomplish. Also if you are unfamiliar with dealing with exr files and linear workflows like I was as recent as a month ago then just know that an exr file is 32bit and linear (basically has a 1.0 gamma curve and is not in a color space like RGB, sRGB, AdobeRGB etc.) and allows you to deal with so much more information with extended latitude (dynamic range) and also individual channels. The video shows just how powerful it is but also how easy it makes it so that you can go back again and again from the single rendered canvas passes from that scene and manipulate in millions of ways. Need it nighttime? No problem. Need some lights on and some off, np.
Also, I just discovered a plugin that may assist with your exr workflow in photoshop but have not tried it yet:
www.exr-io.com
I know I must be doing something wrong, but when I go to the advance tab in render settings I do not find a tab for canvas types there is anyone that can explain what I am doing worng? Trying to learn and I am sure it is something obvious
Esha also created a tutorial:
https://www.daz3d.com/daz-studio-training-intermediate-03--render-canvases-and-postwork
@crabbef_6487cf2881: That is weird, as this is what mine looks like. Maybe you have to click on hardware?
Try clicking next to Hardware - I suspect the the colours are the same for text and background, though I thought that had been dealt with.
Wow I knew it had to be simple. Thank you Richard. The words show up in while as I roll over them with the mouse. I really appreciate your suggestion.