Adding a fill source in an iRay HDRI environment.
I setup a HDRI environment, Dome & Scene, Infinite Sphere w/ Ground, Draw dome, add a HDR image with everything else as default.
The iRay render looks fine and any objects added show shadows as expected from the lighting of the HDR image. However, when adding a fill light there are no shadows added. I know the basics of iRay so understand this is as it should be. I've tried adding planes with the Create Advanced iRay Node Properties with the plane Display=Enable iRay Matte=On. All that happens is the expected fill light shadow is cut out of the plane (see attachment). I've made sure to start with new scenes with defaults on everything. The scene only contains 1 camera, sphere, plane and spotlight. In the screen cap render the plane is at its default location when created and just scaled up to cover the render area.
Any ideas on why this is happening would be greatly appreciated.
Thanx,
MT
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
Your post doesn't make clear why you're using the matte feature. Let's start there. You don't need a matte object to get shadows from a separate fill light, and it is not correct that you shouldn't have them. In Iray Photoreal, all lights should cast shadows.
Not fully understanding your question, let's take a stab at it. Remove the matte surface (its use as a shadow catcher etc. is only a byproduct; that's not what it's fundamentally meant to do).
Select Scene Only in the render tab, and experiment with placement and luminosity so that you get the fill effect you want. When in Scene Only, you won't get the light from the HDRi, only the scene light(s) you've added. Note that most fill is soft shadow, so you want to change the emitter geometry for the spotlight from Point to Disc. Enlarge to diameter to at least 30 (30 centimeters). The larger the emitter, the softer the shadow detail, but the higher you must dial up the luminonsity.
(The luminosity is in lumens, which is the total light output. As the emitter size is inreased, so is the area of illumination. You need to compensate by increasing the luminosity.).
Once you have the balance of the fill, you can choose Dome and Scene to render with both the environment dome and scene lights. Make any fine-tuning adjustments between the fill and environment intensity.
Be aware that there are no shadows from spotlights on the Iray virtual ground plane. To see shadows on the ground, you must place geometry there.
Tobor, thanx and I'm using an iRay based matte plane as a shadow catcher per all of the forum and web searches I've done. As a master photographer of 35+ years I'm well aware of light/size/source parameters as to softness and shadow definition.
I've tried emitter based geometry and spotlights for key, fill, rim, etc., all the typical photography based lighting. However, as the HDR environment doesn't show any of these sources shadows it isn't realistic. Your last statement, "To see shadows on the ground, you must place geometry there." is exactly why I was using a matte plane. However, nothing I've tried will generate shadows from the additional light sources.
Thanx again,
MT
I'm still not clear why you're trying to use the matte surface/shadow catcher in the first place. Why do that if you want to show shadows? To see shadows on the ground or against an object, use an ordinary Iray surface. Start with a geometry, and apply wood, concrete, plastic, fabric, asphalt, or whatever material you want to show.
I think to get a good response here you'll need to be more clear what effect you're trying to achieve. The comments in your second post are at odds with the first. At first you said
And then in your recent post said:
It's unclear by your statements whether the HDRi is providing shadows or not.
Tobor,
New scene
Add HDR environment image, set dome draw on, add a sphere dropped to ground, render with default iRay settings, sphere shadow is cast as it should be.
Same scene with 1 added spotlight or light emitting geometry placed close to sphere and pointing at sphere, render with default iRay settings and sphere shadows shows only for HDR environment and not for any added light.
I can't make it any simpler. If a photographer shoots outdoors, we often add one or more lights in the scene for light sculpting and these lights will often cast shadows. So an iRay HDR environment that doesn't render shadows for any additional light source can't be used for any type of realistic photo based scenario without additional post processing in Photoshop.
And yes I can add a plane to catch shadows but that defeats the purpose of the HDR being used for the scene background.
Thanx,
MT
Have you tried lowering the light intensity from the HDRI, it might be too bright and is overpowering the light from the extra light source.
That would be my guess, too, as the extra lights should be casting shadows. I'd first take a look at the intensity of the HDR and then look at the settings on my lights. One thing you might try, is to temporarily turn off the HDR and just test out your lights in the scene by turning the Environment settings for Scene only while you get your lights exactly where you want them and then turn on the Enviroment back to Dome and Scene and see if it makes a difference. Then make further adjustments to get the whole scene the way you want it to look.
Thanx guys but as a master photographer the light balance issue was one of my first guesses but alas it makes no difference. I also turned off the dome and used scene only to adjust light position but that really doesn't matter as regardless of how bright the secondary light is or where it's placed the shadow won't render on the HDR ground.
Thanx again,
MT
I already addressed this. You are looking for a shadow on a virtual ground plane that belongs to the environment dome. Spotlights and point lights won't cast shadows here, but they DO cast shadows onto other objects.
I''ve attached render results to demonstrate. The images are self descriptive by their names.
1. The HDRi, part of the environment dome, casts a shadow onto the virtual ground.
2. The added spotlight does not cast a shadow onto the virtual ground. To see a shadow on the ground, add geometry, and shade it.
3. The matte feature is not really for catching (show or hide) shadows. It's for composition matting.
4. Though the spotlight does not add a shadow to the virtual ground, this shows that indeed a shadow is being cast on other objects.
For the future, it's helpful if you fully explain what you've tried. No one is a mind reader, so no one knows you're a "master" at anything, and we try not to assume.
As for being a master photographer, I have 15 years on you. We're both speaking the same language, but it helps to fully descriptive of what you're after. From what I now understand, you want to use an HDRi image for both lighting and background, and you want the shadows from the added scene lights to be cast onto the image at the ground plane. By now, I think you know the answer to that. If you want additional shadows cast on the virtual ground, modify the HDRi. It can be done in Photoshop by editing the 32-bit HDR/EXR, and adding more light sources in the appropriate places. An HDRi isn't limited to just one light source. You can simulate a full studio setup with just the image, and no scene lights. In fact, this is quite commonly done.
It's a known problem that the built in "Ground" only works properly with the HDR.
It sounds like the latest Iray still has this limitation.
We've discussed it before, in the forums, I can't remember if we found a solution.
Not quite. The infinite/distant light will cast a shadow onto the virtual plane. It's an odd duck.
(Edited to show the effect.)
Tobor,
If you got 15 years on me then you should have read this in my first post:
The iRay render looks fine and any objects added show shadows as expected from the lighting of the HDR image. However, when adding a fill light there are no shadows added.
The above is the gist of the whole thing in that the ground plane of the HDR environment won't show shadows for spots or emitters. Haven't tried a distant light but I don't see wasting any more time with this as life's too short. I'm going back to Vue as I thought I'd give DS a try being I use it for flash lighting animations but only with 3Delight.
Thanx for all the other replies as well but I consider this case closed.
MT
I read it several times. You made no mention of shadows *on the ground*, or that your intention was to use the HDRi image and not just its lighting. Of course there are shadows made by the scene lights. They show on scene elements. As I already noted, they don't on the virtual ground plane, which is not a scene element. You weren't specific about what you meant by shadows, and I addressed the generalized comments you made. Your screenshot is at best minimal, and not at all clear as to your intent by the use of the matte object feature.