Arnold Shadow/Matte material that receives shadows AND light?

[tonyinseattle]

Does anyone have any ideas for creating an Arnold Shadow Matte material that can receive light as well as shadows? For example, if I have a photograph of a road at dusk, and I want to render a car that casts shadows on the road but also lights the road with headlights.

The shadows are no problem. But I see no way of receiving light.

I'm using 3ds Max 2019 and the latest Arnold.

Thanks,

Tony

[hagen.deloss]

Hello @tonyinseattle,

Thanks for posting your question in the forums! I would love to help you figure out how to get you the right materials for this project. 

So from my understanding, you have a scene with a car and a road, and you are looking to create a Shadow matte to receive both shadows and lights on the shadow matte?

It looks like what you want to explore is Arnold AOV's, which is probably your best bet on rendering out a light as a separate layer. You can then edit the shadows and lights on their own layers in your editing software.

If I misunderstood your question, or if the tool I suggested doesn't work for your situation, please clarify and we can continue troubleshooting! I would also be up for helping you out more if you have any more questions about how AOV's work. Talk to you soon!

Please select the Accept as Solution button if my post solves your issue or answers your question.

[tonyinseattle]

Hello, @hagen.deloss / Hagen... Thank you for your reply.

I am somewhat familiar with AOVs and have been playing with them. However, if I cannot get light to cast onto the shadow/matte material, then I'm not sure how I can make it "appear" in one of my AOVs? I just did a test with various direct diffuse and indirect diffuse AOVs and it did not work. I'm sure I'm doing something wrong! 🙂

Please take a look at the attached scene. I have a curved background onto which I've applied a Shadow Matte material. I've placed a simple box and sphere on the beach scene. Above the box and sphere, I've placed a pink spotlight. You can see the pink from the light hits the box and sphere, but it does not cast pink light directly onto the beach scene. You can see shadows from the pink light, and you can see the pink light hitting the sphere reflected in the sand. But you cannot see pink light cast directly onto the "beach," giving the sand a pink tint. Make sense?

Thanks for your help!

Tony

[hagen.deloss]

Hi @tonyinseattle,

Sorry for the delayed response! I downloaded your file but it's not opening, we may not have the same version of Arnold installed, I'm getting the error, Would you send me the file in a private message? maybe the zip file is cutting the download short or something.

Also, that's odd that the ground material isn't receiving any of your lighting, but its receiving your shadows, would you mind taking a screenshot of your material settings for the ground plan Shadow matte, and also showing me what angle your light is at? It looks like you have a really soft pink light that isn't effecting the ground plane much. Here is the documentation I could find on Arnold AOV's in 3DS Max. It looks like if you can set up the AOV for your light,  you can see how it effects the ground plane, and adjust the lighting from there.

"Each light object has an AOV parameter which writes out the light contribution to a separate AOV with a corresponding name. Available per-light AOVs are displayed in the lists with the (light group) postfix once any of the lights have an AOV light group defined."

I went into my Arnold light settings and scrolled down to the bottom until I saw AOV, and I named it Light_1, I then went into my render settings, and added Light_1 into my custom AOV's and it appeared on my list of AOV's in my active renderer, so that's a step in the right direction...though it's still not rendering anything! Here are my settings so far.

I will continue poking around and I will eventually make sense of these settings. Sorry we haven't been able to figure this out right way, thanks for being patient 😄

Please select the Accept as Solution button if my post solves your issue or answers your question.

[tonyinseattle]

Hi, @hagen.deloss / Hagen... I sent you a link to the file. It's Max 2019 and Arnold -- both latest versions. 

Yes, it is odd that the shadow-matte material is not receiving any of my lighting. However, I'm beginning to believe this is by design and not an error. But, if that's true, then I'm not sure how to accomplish this effect.

I've played around with AOVs in all different ways. However, I'm pretty sure that if light is not cast upon a material, it doesn't otherwise show up in an AOV. And I've turned the light waaaaay up so that if there's any light being cast upon the shadow matte material, it would clearly show, but there is absolutely none. The material picks up shadows only.

You should be able to open my file, see the pink light and all of my settings. I hope that will give you a clearer idea of what I'm trying to accomplish. I just want the pink light to cast a pink hue directly onto the sand of the beach, just like a pink light would in such a situation.

Thank you!

Tony

[hagen.deloss]

Hi @tonyinseattle

I looked at your test scene and it definitely illustrated what you wanted  from the AOV! Thanks for taking the time to provide that context for me 😄

Are you are using a shadow matte to have more control over your scenes lighting so you can composite these elements together? Besides the Solid angle documentation, I haven't been able to find much else.

You're right, I think the light isn't interacting with the shadow matte ground plane because it's not designed to. Having light and shadow on the same AOV pass wouldn't make much sense to composite. Though in the above linked document, you could try exploring the specular settings.

I would suggest duplicating your scene, and rendering out another light AOV so you can composite the lights and shadows together. Though I'm not sure the light will ever interact with your scene the way you want without actual ground geometry for it to bounce and reflect off.  

Let me know if this additional information helps!

Please select the Accept as Solution button if my post solves your issue or answers your question.

[hagen.deloss]

Hi @tonyinseattle

I wanted to check back and see if my post helped you with your problem. It would be super helpful if you could add a post with how you decide to proceed, and your results. That way other Community members can benefit from your process

Please select the Accept as Solution button if my post solves your issue or answers your question.

[tonyinseattle]

I have reached a dead-end on how to accomplish this. Does anyone else out there have any ideas?

[madsd]

Composit, you just need to know how to do it.

It is very simple, work with layers, ADD.

Watch attached video tut I just did based on your scene.

[hagen.deloss]

Hi @madsd

I'm not seeing an attached video, you may want to try embedding a youtube video instead. Excited to see how you would composite this!

[madsd]

I had to take it down because I saw something only I should see in the video :)Will redo it tomorrow.

[tonyinseattle]

I'm looking forward to seeing it, too, when you repost it. Thank you!

[tonyinseattle]

@madsd, any chance you'll be able to repost that video soon? I'm looking forward to seeing your solution!

[madsd]

Yes, sorry.

I was away, looking at it right now. Had to take the video down that day and didnt redo it.

[madsd · Accepted solution]

Attached.

[tonyinseattle]

Hey, @madsd ... thank you! This looks like the best solution. Thank you for posting.