Cycles Shadow Catcher

I’m sorry to say this, but the Cycles Shadow Catcher is not yet ready, In my opinion. Whilst it will catch shadows, that’s as far as it goes. However, caustics, and reflections (also a mainstay of catching shadow - even just every day reflected light is missing).

Is this in the pipeline, because I would love to see the third party solutions obsolete, purely on render time alone. The shadow catcher is much faster than third party multiple pass options, and if all you need is shadows, then fine. Unfortunately, shadows alone is never going to be enough for production renders.

In the interest of full disclosure, I released an addon which does reflections, caustics and reflected light. I would like to be made obsolete, since my method also uses multi pass and tweaked in compositing methods.

Examples:

Blender shadow catcher


Custom:


Seriously? Any links, sources, comparisons, studies, examples or… ?

E.g. Basic Composite Workflow Comparisons by Jeff Patton

Thats my opinion too. After trying it, I immediately went back to the old shadowplane - divide setup, where you need 3 Renderlayers.

Out of curiosity, what if you placed the ball on a green background ?, would the lightspot becomme green ass well ?.
(not thinking about greenscreens)

for animation starters is simple, fast to set & good enough… tho, you’re kindly welcome to develop the code further or use custom solutions as you have shown

I suspect for a quick and dirty animation, the built in may be enough. But for production, there’s more to shadows than just shadows. Reflections and caustics are an important part. Even removing other hacks, such as yafaray caustics and a separate render for reflections, then putting it all together, many 3rd party “from the render” solutions offer so much more.

However, I do appreciate that this is early days, and as I said, I would love to be redundant in this regard. I more interested in the roadmap, and will it include caustics and shadows.

For info, the example was the simplest I could come up with. If I’m looking for complex caustics, for example, I would probably use a yafaray/cycles composite, though not the most useful for animation.

Just out of curiosity, how does shadow catcher work on most other programs? Can they also capture caustics, reflections and colored lights?

I honestly don’t know. When I created my plugin (which if I’m honest just automates setting up render layers, scenes etc. You still need to setup the materials and put stuff on the correct layer) I did so by going through so many shadow catcher tutorials and pulling together the best of into one setup.

I’ve only used C4D extensively previously, and that was shadows only. Coloured lights should be consistent regardless of the solution, since the same lights are used. I added compositing nodes and a couple of easy sliders to colour correct the shadows and reflections, but again, more of a time saver than anything innovative.

I’ll use mine for quick and easy, but for a final render, I’m more likely to render separate passes, including masks and then bring it all together in something like GIMP, where I can refine the colour balance and correction manually per layer anyway.

EDIT: I should add, looking forward to re-texturing my go to test scene using the principled shader, and see how well it plays :slight_smile:

With colored lights I mean something like this (the intensity of the lights are animated):
http://pasteall.org/blend/index.php?id=46970

If I set the plane as Shadow catcher, the intensity of the shade varies according to the intensity of the lights, which is fine. But then I can not get the colored lights.
So I wonder how other software solves that. Do they have some kind of light catcher or something?

@Yafu, check the link i posted above :wink:

With Renderman you can tag an object as a holdout. When you render that object will only show captured light and reflections from other objects in the scene. You can also create a shadowpass automatically from an occluded and unoccluded lighting pass (which is the same thing Cycles shadowcatcher does I think).

Yes, there is just way too many things wrong with current shadowcatcher implementation in Cycles to be usable in any kind of serious production scenario. I’ve made quite a detailed description of all the problems on pages 4 and 5 of this thread:

I admit that I did not open the link before :o
Thanks.

@ Geographic

Sorry, I missed your question, but to answer (I assume you mean does the ground plane affect the colour of the shadows/caustics) I can say categorically “yes”.

These are both the identical render, with the only changes being that the HDRI is disabled in camera for the first and replaced with a BG colour (HDRI is still used for light/reflections), and the shadow catcher is given a matching colour. If you were to use a background with an image and wanted the variation across the different colours of the background, it can be done by setting up a diffuse texture on the shadow catcher correctly. I chose a solid colour purely for illustrative purposes, and you can see the difference just based on the BG.

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