Welcome to od|forum

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.

aeroba

houdini shadow catching?

hello

 

I see the black grid in the render. I want the shadow catcher to be in visible in the render and see only the shadow that It catches ( like the middle image). what do I need to do please?

 

thank you 

Share this post


Link to post
Share on other sites

mestela 

thank you very much. It was very good setup and It helped me a lot.

 

I have a question:

 

the thing I want is a clean ( just shadow ) in the alpha and a good shadow composite in the beauty render , like the images. but  I get a black plate in the render (however the alpha is fine)

( using shadow matt material assigned to the plate)

 

in maya It is simple as that to use a background shader( with arnold , shadow catcher),

but in houdini I'm stuck!! , I can't get rid of the black plate in the render.

 

hope It makes sense.

post-14243-0-38100200-1454406092_thumb.p

post-14243-0-60249500-1454406375_thumb.p

Edited by haaranoos

Share this post


Link to post
Share on other sites

Unless I'm misunderstanding your question, isn't that in the example hip I linked? I had to look at that hip again and do a render, the beauty channel is a reasonable composite, the alpha contains a matte for the shadow. 

 

post-7292-0-99966300-1454409146_thumb.pn

 

 

As an aside, the guy who wrote our in-house pathtracer at work would get pretty worked up about shadow mattes. Pointed out that once you start doing multi-bounce everything, colour bleeding this into that, then the concept of a shadow matte becomes vague and murky. Took a while for us to adjust, but we're now about 99% shadow matte free. Compers aren't so convinced.... ;)

 

-matt

 

Share this post


Link to post
Share on other sites

matt!

yes I did render again and makes perfect sense now. thank you

 

 

- by any chance do you know how to create arnold shadow catcher in houdini ?  ( with arnold shaders)

 

- I've attached the image of the shadowmatt material. this setup should work also ( I mean we should see the color ) but I get black plane. why is it happening?

post-14243-0-33254900-1454416252_thumb.j

post-14243-0-49067900-1454416272_thumb.j

Share this post


Link to post
Share on other sites

O.k.. :)

 

I figured it out.  now It works perfectly.

thank you again.

 

I wonder why shadowMatt shader doesn't provide this kind of setup by default. 

Edited by haaranoos

Share this post


Link to post
Share on other sites

I'm using shadowmatte with arnold, what is your concern?

Share this post


Link to post
Share on other sites

I know how to use it in Maya but i can't get it going in Houdini. I'v made a shader with a shadow matte and put this on the plane but i don't get the shadow seperate. Look at the hip. 

 

generic_studio_outdoor_v0100.hip

Edited by HGBarca

Share this post


Link to post
Share on other sites
On 2/7/2017 at 11:22 AM, 6ril said:

I'm using shadowmatte with arnold, what is your concern?

@6ril Hi, I'm trying to use the shadow matte in arnold for Houdini, however it is only usable in ArnoldVopnet, and I'm not sure what I should connect as the input of the shadow_matte vop node. Currently it is rendering RGB and alpha totally opposite. Where I get shadow in alpha doesn't have anything in RGB, vice versa. If you don't mind to explain some of the details or share a simple example file will be great! I tried to find example on the documentation site, but didn't find one. Thank you so much!!!

Share this post


Link to post
Share on other sites

oups! sorry, I haven't checked ODForce lately.

@violalyu@HGBarca

For the simple case ( ie sphere on a plane) 2 ways to use shadow matte :

-render without BG and include BG in post (most flexible option for me) : just apply a shadowmatte material to the plane. It will be black in RGB which is fine as the Alpha channel will be white only in the shadow.
best way tho is to use AOVs to fully separate that shadow, or just another ROP with a take where the sphere is not visible to cam.

-make it all at render time : a bit more difficult as Arnold weirdly doesn't allow camera bg image, and the OUT_environment will allow only Sky or flat color (as far as I know). So you'd have to do a little trick (mapping you bg on a plane facing your cam, with "visible to cam" as the only option checked in the Arnold Visibility tab of that plane). And in the matteshadow shader, you need to connect the bg image into the background color input of the shadowmatte node.
But, if you BG is an hdr (spherical map) then you can avoid the "plane facing cam" hack, just make an env shader with image into sky into out_env (in a arnold vop in shop) (don't forget to uncheck diffuse glossy otherwise it will light up your scene).

 

not time to make a hip now, but it's I'm unclear, let me know : /

Edited by 6ril

Share this post


Link to post
Share on other sites

Thanks @6ril! I was able to have it working the other day, but there's only a shadowmatte vop, so I just connected the output to rgba, not sure if I was doing the right thing but the result seems to be correct.

Share this post


Link to post
Share on other sites

I used the wrong terminology, I said shadowmatte "material", which is wrong. It is indeed a vop, and I use it just like you (into color diffuse).

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now