Shadowcatch Surface Iray
jeff_someone
Posts: 254
Is there anyway to create a shadowcatching surface in Iray similar to the way the floor shadow is rendered? This would be a great capability for the type of renders I do, so any advice on this is greatly appreciated.
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We’ve created a pointer page that shows various threads on Iray that have been very helpful. You might want to check these pages for the topic you're starting. Rather than start new Iray pages, please check these sources first since it keeps the places to look for information simplified. These are also pages where many Iray users have been discussing Iray topics and so may be much more helpful to you. When there are dozens of threads, one forgets where they saw what and information may be posted that is very helpful but gets missed.
http://www.daz3d.com/forums/discussion/56788/
In the REnder settings, go to Environment and turn on "Draw Ground" (see image)
Yes, I know there's a ground/floor plan that acts as a shadowcatcher in iRay. However, I want that same functionality (catching shadows) on other objects, not the just the ground plane. In 3Delight you can create a shader mix that does this but you cannot apply a shader mixer shader to surfaces in iRay (well, you can, but it ignores it). In iRay I've not seen anyway to do this. I would really appreciate any help on this.
Thanks,
Jeff
Theoretically it should be possible as the Draw ground is in effect a shadow catcher. What you need is a way to move the surface setting from the ground to another object. I haven't been able to figure out how to proceed with this through either the shader mixer or an mdl setting.
1.) Select the object in the scene that you want to behave like a "shadow catcher"; in Iray these are called "matte objects" and they do more than just "catch shadows"
2.) In Content Library pane, navigate to and load DAZ Studio Formats > My DAZ 3D Library > Scripts > Utilities > Create Advanced Iray Node Properties; this script is provided by the Default Lights and Shaders package
3.) In the Parameters pane, navigate to and activate the Display > Rendering > Iray > Enable Iray Matte property
-Rob
Awesome thanks Rob!
Hi all,
I'm trying to get a shadow catcher type surface working, and I'm getting nowhere. Have any of you done it, and could give pointers?
I have done what Rob says, but then my object simply doesn't appear in the render...
thanks,
Steve
The idea of a shadow catcher is that it won't appear in your renders, it just catches shadows that fall on it. Is this what you are trying to do?
Yes, it works for me with a simple photometric spotlight. Are you using something more complex?
Using geometry set as emission surfaces, no shadows are "captured" at all. Doing the same with a basic HDR environment also doesn't work.
Just tested HDR and other lights and it seemed to work okay.
Edited for correction.
I seem to only have issues with Emissive lights when Dome and Scene are active in render settings.
First image shows basic scene setup with spotlight. The black at the bottom is the shadow catcher a squashed sphere in this case.
Sun, HDR and Emissive only
.
And Emissive with Dome and Scene, the shadow catcher appears to be catching some light as well. But overall everything appears to be working. Maybe there is some particular setting you have modified in the scene?
I'm really starting to like these forums to btw
OK, thanks for this - I'll relook at my setup. Does the Matte Object require any specific surface setting to be set?
Maybe I'm confused, but I thought all objects caught shadows? Is this only for rendering things in a blank environment? I've done plenty of scenes inside buildings and shadows were working fine.
its for adding shadows from a scene to a 2d background plate.
Thanks Rbtwhiz and Design Anvil! this hint is exactly what I was looking for.
However, in my Daz studio 4.8 installation, the folder My DAZ 3D Library is empty. Also I cant’ find Iray shaders anywere.
Any advice?
Thank you
How did you isntal the content? Did you install Default Lights and Shaders (after the release of DS 4.8) at all?
Oops...
I asuumed that those were already in the DS default install...
I suppose I was wrong... So, where can I find "Default Lights and Shaders" addon?
Thanks!
It's one of the packages that come with DS, but it isn't installed automatically.
This is amazaing! it does reflection and blocking too! EEEEEEEEE!!
I'm so happy right now
This fascinates me! I played around with it earlier today and made my own little experiment.
1. screenshot showing I have a plain MPC as the bg/floor prop
2. screenshot of my rendered transparent image inside DS4.8Pro. Shadow is visible, but not the background. Script run on MPC and turned ON as Iray Matte node.
3. my final flattened image in graphic software with my own added background.
So it's awesome to know this information so I can render a shadow using another object as the shadow catcher with this script, and that's all there is to it! It really works!
You'll have to click on the images to make them full size. The forum format here confounds me when I have to add an image.
Guess I don't know how to add multiple images in this "new" forum format. Here's image #3.
click to see full size.
Hmm.. don't have the script, not finding the package. :(
Nevermind, found the stuff.
Has anyone experimented on the best color to have the item you set as a shadow catcher?
There are several fantastic tuts by Mec4D over at Youtube for shadow catching in Iray.
And all you need is included in Daz. Here is one of three: https://youtu.be/6vaUXdZzy0c
I was overwhelmed...
Not so fantastic. Tests have shown her instructions of making the plane black just darkens everything. Making it white, and it's catching the shadow, AND the light color, so it's not useful, either.
I've eliminated everything in the scene that can cause shadows but what I need. I've turned off the hdri. so just the scene lights are casting..but I'm not getting what I need.
I first set the object material to "!Iray Uber Base", from the "Presets" tab, in the Surfaces window. Then I run the script on the object to turn it into a Matte Object. (Not having an IRAY material may "add" things which daz will assume need to be there, when converting 3DeLight materials into IRAY. With !Iray Uber Base, you can set the Iray values and leave nothing to internal inference.)
The settings I use, which do not capture colors or cause "reflections" or pick-up reflections, are these... (The rest are default settings)
Base Mixing = (Weighted)
Base color = 0,0,0 (Black, so it reflects nothing and absorbs everything)
Refraction Index = 1.00 (That is the lowest it can go, it is normally at 1.50. You don't want it refracting, as it is not glass or water. Not sure why that is even a setting other than 1.00 or not 0.00 for "none".)
Share Glossy Inputs = OFF (You don't want it to have any gloss {reflections} at all.)
That seems to output only the shadows. (However, if you are simulating an object in a scene, you woould want some of that other stuff, for realism.)
P.S. I also turn "Cast shadows" to OFF, unless you want it also casting shadows. However, you seem to be using it only as a wall, not as inline "objects". If simulating objects in a photograph, you want it off, as the photograph objects already have the shadows in the picture. However, it seems not to actually cast shadows, even when told to do so. It may, somewhere...
Thanks for the comments.. It helped learn some of why to do things, but that worked worse than the previous attempts, giving me total blackness where there should be at most a smattering of light grey (1)
I followed your settings (2) and they make sense... I don't have a "Cast Shadows-off" fucntion (3).
(the shadow I'm not catching is there in pic 4)...looking at it, I'm starting to think to use that method.. a white backround which takes the colors, then use photoshop levels to turn the beige to white and use opacity and multiplicity to get me my effect...I wantted to do the tricks inside Daz, but in theory, photoshop should do it).
But wouldn't it be a little hard selecting the 'almost invisible' plane in Photoshop and then making it invisible? I'm sure there's a way in Daz to do that, but I can't find it.