I successfully created depth map shadow in Houidni and rendered with renderman. But I found the shodow map's edge created by Houdini's “autogenerate depth map” is a bit too hard!
Does anyone know how I can created softshadow in Houdini? (I will be using renderman to render.)

thank you for your attention

brucelay
edge created by Houdini's “autogenerate depth map” is a bit too hard!

The “hardness” of the shadow-edge has absolutely nothing to do with how Houdini generates the shadow maps, and everything to do with how the shader samples the map.

To “soften” the edges, add one or more of the following parameters to the shadow() call inside the shader:

“blur”, “sblur”, “tblur”, “width”, “swidth”, “twidth”, and “filter”

All of the above parameters have to do with filtering (or “softening”) the shadow map.

Also, I very highly recommend spending some quality time reading the 3.2 RiSpec (which you can get from here [renderman.pixar.com]), and turn to page 145, where it talks about texture mapping functions.


Cheers!

There is a “softshadow” option in MtoR (Maya). It will create mutiple shadowmap to generate a softshadow effects. I just want to know if this “softshadow” function is avaiable in Houdini.

Thanks

I'm not certain - did you check the Rman-Ator shaders that ship with Houdini?

MTor is a plugin that has some precooked shadercode and an interface to Maya - Houdini doesn't really have an equivalent(apart from some of the Ator shaders mentioned above). It rather requires you to handle the shaders yourself, and now with 6.2 will let you output rman shaders from the Vex builder. Houdini supports the shader you mention inasmuch as you can write or utilize the code that comes with renderman, Houdini, or you write yourself. As far as interface - that's all native to Houdini…it's very complete.

Also, just to be clear, that's one particular way to deal with shadows - a pseudo-area light using that multiple light model. I've personally found it's dead slow in renderman, and Mario's initial comments were true - what you really need is to filter your shadmap in the shader.

I sense what you want is MTor in Houdini, which isn't there. However, those ATor shaders may go some way towards that…

Cheers,

J.C.

Hi brucelay,

I see what you mean now… and the answer is no – there is no single button in Houdini that will create lights in some pre-canned configuration around your “real” light, then proceed to generate “minmax” shadows from each one, and finally alter the shadowmap parameter to your shader to include a comma-separated list of these “auto-generated” shadow maps.

There's also no button to create 6 orthogonal shadow maps for point-light shadows (if you're into doing them that way)…. and… well; there's a variety of convenience buttons like that, which are missing.


All's not lost however

You do have the ability to include pre-render, and pre-frame scripts in your ROPs. You could use these to generate mountains of shadow maps for you.
The thing is that this “Soft Shadows” area-light-shadow-hack is a very PRMan-specific thing, and Houdini is a “generic” tool (and we like it that way ), whereas MtoR is a very specific tool designed to cater to the needs of a very specific renderer.

Cheers