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About blue_riviera

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  1. hey, thanks. catched your drift... even extended it a bit: 1. to properly emulate maya's 'isolate select', one can first create a new take (with 'auto take' on), select the object(s) to isolate, hide the rest, and store it in the take. 2. it's good to know that the e, r, t tools work for multiple objects (i always tried the 'default handle' by pressing Enter).
  2. Hi, First, sorry for these very basic questions but (believe it or not) i looked for the answers in the forums first, but not found any (perhaps these are one of those questions with the answers _so_ obvious... ). I come from Maya, and although I appreciate Houdini's viewport-related features, I'm still looking for some features I couldn't easily replicate. How can I... - do "isolate selection", where I select a single (or a few) /obj object, and Houdini would (temporarily) hide all the other objects. - move multiple objects with the transform handle/manipulator? - get some stats about the geometry in the viewport (no. of polys, etc.) similar to Maya HUD (should work for multiple objects, so pressing MMB on a SOP is not the same) - snapping: how can I snap along a single axis? (in Maya: if you hold on to a single axis of the handle/manip with snapping enabled, it will move and snap along that axis only) Snapping in general feels a bit more 'uncomfortable' compared to Maya, I usually fall back to the Orientation Picking function (which beats M's most snapping tools, hands down -- the Construction Plane rocks! ). imre
  3. Hi, I'm trying to bake occlusion into a point cloud in a surface shader. I disabled the vm_hidden parameter in mantra (so in the interface "Enable Hiding" is off), and I still get some strange results. As you can see in the attachment image, the pointcloud appears okay from the camera point of view (the pointcloud can be re-imported in a SOP network btw, which is quite cool). However if you check the back side, it appears as if for some parts occlusion wasn't calculated at all, for others (teapot body), there is something that shows some resemblance Any ideas on how to address this are appreciated Thanks imre
  4. reflection distance-falloff

    thanks for the tip... meanwhile i found what i was after and it was (approximately) the following (i'm not in front of houdini right now) -- something like this: float ray_length=0.0; reflectlight( (...) , "ray:length", ray_length); this returned the length of the reflection ray in ray_length. i'll check your hip file as soon as i can though... thanks! imre
  5. reflection distance-falloff

    Hi, I'd like to implement distance-based falloff in my ray-traced reflections in mantra. What it means is to basically fade the reflection component to black based on the length of the reflection ray. I'm coming from a mental ray shader writing background -- in mental ray you can access all details of a 'child' ray after you traced it (so you can just take the length of the child reflection ray, and use it to fade your resulting reflection component). I've found the mechanism to pass information between shaders when doing ray-tracing calls (as Mario mentioned, all things described in the gather() function's help also apply to all other ray-trace functions). For instance when tracing a reflection ray, it is easy to query the ray length in the shader _of the hit surface_. However I'd need that information in my shader (that calls the reflection tracing). In mental ray this is something pretty straightforward. Is this possible in mantra? thx imre
  6. (noob) labeling child rays

    An example: I'd like to attach a label or tag (let's say, a string) called "occlusion" for rays that calculate occlusion, or "refract" for refraction rays, etc. (similar functionality exists in mental ray) This way, my shader that handles the child ray would know more details about the ray type, and act accordingly. imre
  7. (noob) labeling child rays

    Hi, (Noob question again -- I read about this in the forums, but of course now I need it I can't find it...) What I'd need is to be able to attach "labels" to child rays somehow in mantra. (To pass on more detailed information to my own shader(s) that deal with those child rays). Any idea on how to do this? Thanks imre
  8. irradiance caching

    Thanks for the info, this is nice to know I was (and still am) worried about the "partially implemented" part when I started experimenting with it (trying to cache simple irradiance() calls), and the cached version had black spots appeared (I'll try to upload pictures+scene later). And I couldn't get rid of those artifacts, only partially -- where I had to overshoot the various parameters that it became magnitudes slower than a 'regular' (un-cached!) render. (I used an 'own' shader for that test, which was basically a lambert and an irradiance vop, summed, the simplest it can be ) The above mentioned problem only happened with irradiance, occlusion gave much better (ie. proper) results.
  9. irradiance caching

    Hi, (I got no response to a previous post (on a related topic), so I thought of breaking it down to simpler questions... ) I wonder where I could get my hands on _any_ documentation related to the (partially implemented?) irradiance caching functionality in mantra. So far I found close to nothing in the manuals (but this might be my mistake -- sometimes it seems as if the search function doesn't work on the entire docs(?)). Basically what I'd like to read about is that 1) what does this "partially implemented" mean 2) is it of any use in it's current form and 3) perhaps some technical details about it's workings. From what I read on these forums so far, currently some GI-related aspects of mantra are unclear to many people, is that a correct statement? I wouldn't mind to "roll my own" pointcloud based shaders if the renderer doesn't support it out of the box, but it's a bit hard without the tech details. (I'd like to have an end result that is comparable in performance and behaviour to mental ray's final gathering.) imre
  10. (noob) caching irradiance

    Hi, I'm new to houdini/mantra rendering, so this might strike you as a noob question (i tried to find answers on this forum, but to no avail yet). What I'm trying to do is to simple irradiance caching (similar to mental ray, which i use extensively, but i like the houdini/mantra approach too, very powerful stuff). I played around with the 'default' irradiance caching functionality in mantra (including tuning the parameters not published by default). My experiences so far is that 1) when using irradiance caching, black 'spots' appear in the cached result (like a low pass filter is missing from the caching algorithm?). 2) one way to (partially) get rid of these black spots/artifacts is to increase the density of the point cache (reducing the min/max screen space radii), but this makes the overall rendering magnitudes slower than without caching. Btw I'd need this for an architectural visualization project (which is an ideal testing ground for this kind of stuff, ie. all geometry are static, and there's only camera animation). My goal is to cache irradiance (and possibly occlusion) to a point cloud, and use it for fast rendering. Mantra has some powerful pointcloud functions in shaders, so for the rendering part i don't anticipate any problems, but i don't know how to actually build the point cloud "by hand", if i can't rely on the "partially implemented" irradiance caching function. I don't have any idea on how to calculate the irradiance pointcloud. I know occlusion can be done through SOPs (as it's geometry proximity, basically), but for indirect lighting i'd need to evaluate lighting and shading. Is it possible through SOPs? Or is it any way to use the regular irradiance caching without artifacts? Anyway, I'd really appreciate some ideas to give me at least something to start with... Thanks! imre