What do you mean by precaching the whole scene ? However if there is a way to hide the pointclouds in the lightmap stage and unhidding them in the tile rendering stage it would be perfect. (all this in a single pass).
2012/8/14 Vladimir Jankijevic <vladi...@elefantstudios.ch> > why don't you precache the whole scene or animation with the pointcloud > hidden and then read back in the lightmaps on the final rendering? > > > On Tue, Aug 14, 2012 at 11:43 AM, Rémi Arquier <arqu...@gmail.com> wrote: > >> To be sure to be well understood, imagine a scene, composed of a sphere >> with a ICE Cloud Particle around the sphere. The lightmap shader is only >> attached to the sphere (not to the ICE Cloud). When the lightmap compute >> his illumination, it casts shadow rays (and / or secondary rays depending >> of the sphere material), those rays hit the ICE Cloud Particle, and MR call >> the ICE Cloud Particle's geoshader / material for each ray. Even if I can >> put a completely transparent shadow shader on the ICE Cloud, which solve >> the problem of the color illumination, those calls are time consuming : the >> lightmap computation is more than 1000 slower when the ICE Particle is >> present. >> >> So yes, maybe if I could put a custom attribute (like the classic >> visibility flags) on ICE Clouds which tells to MR to simply ignore them >> when casting ray in lightmap stage (the rays would traverse them as they >> wouldn't exist), it would be perfect, but I don't know how to do it. But I >> am not sure, maybe I ask something that the translator or even MR don't >> allow ? >> >> Rémi >> >> >> 2012/8/14 Chris Chia <chris.c...@autodesk.com> >> >>> What I would do is to have your lightmap algorithm look up for an custom >>> attribute in the scene and see what needs to be eliminated from >>> computation?! This would be a hack to solve your unique rendering >>> requirement ;) >>> >>> Chris >>> >>> On 14 Aug, 2012, at 9:55 PM, "Rémi ARQUIER" <arqu...@gmail.com<mailto: >>> arqu...@gmail.com>> wrote: >>> >>> You are right, the ICE Particles cloud are not evaluated for the >>> lightmaps (they don't affect lightmap illuminaton). >>> >>> I would want to compute the lightmaps and the final rendering in just >>> one click on "render". Not using two passes. Lets say that mental ray in >>> "one click on render button" decompose the global rendering into two >>> consecutive stages : >>> >>> Stage 1 - Lightmap computation. The lightmaps, applied on polygon meshes >>> compute some custom user data (whatever) and store them into ram. >>> Stage 2 - Tile Rendering. Other shaders read the custom user data from >>> ram and use it for final illumination of the ICE Particle Clouds. >>> >>> In stage 1, the ICE Particle cloud *must not* be presents for casting >>> ray speed optimization. >>> In stage 2, the ICE Particle cloud *need* to be present since they are >>> visible by all rays. >>> >>> >>> 2012/8/14 Chris Chia <chris.c...@autodesk.com<mailto: >>> chris.c...@autodesk.com>> >>> My qn is: why does your point cloud need to exist in your 'light map' >>> pass? Do you mean that the point cloud still needs to be rendered but not >>> evaluated for light map? >>> >>> Clear my doubt... >>> >>> Chris >>> >>> On 14 Aug, 2012, at 8:39 PM, "Rémi ARQUIER" <arqu...@gmail.com<mailto: >>> arqu...@gmail.com><mailto:arqu...@gmail.com<mailto:arqu...@gmail.com>>> >>> wrote: >>> >>> Thank you Chris >>> >>> Breaking the scene into two passes would solve that specific problem but >>> : >>> >>> 1/ Our custom lightmap shader creates custom data (mental ray point >>> clouds, not maps) and keep them into ram. It would be inefficient to save >>> them then reload them using hard disk. >>> >>> 2/ We already use passes in our workflow and it would complicate it to >>> add other ones just for a shader. We need something "transparent" in the >>> user side. >>> >>> >>> >>> 2012/8/14 Chris Chia <chris.c...@autodesk.com<mailto: >>> chris.c...@autodesk.com><mailto:chris.c...@autodesk.com<mailto: >>> chris.c...@autodesk.com>>> >>> Why can't you break your scene into passes? With the point cloud hidden >>> in the "light map pass"? >>> >>> Chris >>> >>> On 13 Aug, 2012, at 10:20 PM, "Rémi ARQUIER" <arqu...@gmail.com<mailto: >>> arqu...@gmail.com><mailto:arqu...@gmail.com<mailto:arqu...@gmail.com>>> >>> wrote: >>> >>> > Hi list >>> > >>> > I would like to know if it is possible to exclude objects in the >>> ligtmap rendering stage. Specificaly I would like that some of ICE particle >>> clouds not be seen by object beeing sampled (for reflection rays and shadow >>> rays for example). >>> > >>> > I have tried combining a mip_rayswitch_stage plus a transparent shader >>> for the lightmapping rays on the particle material. It works, *but*, the >>> presence of the clouds considerably slow down the lightmap rendering stage >>> since the particles are still hit (by shadows and secondary rays and for >>> nothing). A "rendering lightmap visibilty flag" excluding the cloud for >>> real would be perfect, but doesn't seem to exist. >>> > >>> > Any idea ? >>> > >>> > I could write some custom MR shaders and custom plugins if necessary. >>> > >>> > Thank you for help >>> > >>> > Rémi >>> >>> >>> >> > > > -- > --------------------------------------- > Vladimir Jankijevic > Technical Direction > > Elefant Studios AG > Lessingstrasse 15 > CH-8002 Zürich > > +41 44 500 48 20 > > www.elefantstudios.ch > --------------------------------------- >
