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Nicholas Ralabate

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Nicholas Ralabate last won the day on October 18 2019

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About Nicholas Ralabate

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    Nicholas Ralabate
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  1. How to apply displacement in shaders

    You just bind in your Cd attribute and then use that to drive the displacement amount. I included a minimal example, but the principle is the same when using premade shaders like Classic/Principled. If you do it yourself don't forget to turn on the vm_displacebound setting on the object. nr_simple_displacement.hiplc
  2. How do Mantra lights know which light shader to use?

    Thank you, thats's great info!
  3. I can dive into the light and see the hlight OP, and I see the relevant SOPs but I don't see where the light shader is wired up. I can also expose the hidden render parameter for light shader but that just gives me a blank field. How does a light know which light shader to use? Also, are there any differences between light shaders between H8/H9 approaches? I am mostly concerned with PBR backend. I see in $HH/Vex/Light there are some light shaders assigning to the Cl variable but I'm not sure if that is specific to raytracing backend or if it applies to both raytracing backend and PBR backend.
  4. Magic Spell

    cool! whats that crazy refractive effect you did in comp when the first spell hits the troll?
  5. Volume Displacement Houdini using Mantra and/or Arnold

    for texture projection over volume, you can just use the toNDC VOP in mantra... it will convert every position to a value in the [0..1] range which you would then plug into a texture VOP
  6. Houdini Mac user population

    I used a 2012 MBA (4C@2Ghz/8GB RAM) to learn Houdini for the past few years (mostly SOPs and POPs)... it was ok. I had a couple of problems with the OpenGL viewport crashing when H16 first came out, but that was eventually fixed. P.S. I since moved on to a simple Linux box (8C@3GHz/64GB RAM), a basic build with a ryzen and a potato gpu ended up being cheaper than another MBA/mini (I can't afford the fancier stuff).
  7. Any way to layer with PBR Metallic Reflection or PBR Diffuse on top?

    Thanks~! I didn't realize that did energy conservation, I thought it just lerped the bsdf!
  8. Question about hair shader source

    Hi all, I am trying to level up my Mantra knowledge by digging into the source code for some of the shading VOPs I use all the time. I am a bit stuck though on two things: 1. When I right click and choose "Type Properties" on pbrhair_tt I see that it calls the VEX function hair(), but when I look at the source code for that function (in $HH/vex/Surface) it in turn is calling wireblinn() and wirediffuse(). I cannot find the definition for those two files anywhere. Where should I be looking? 2. I see that there is a hair_eval.vfl and a hair_sample.vfl in $HH/vex/CVex... these seem to define the bsdf, but I don't understand the connection of the hair() function mentioned above and this bsdf function. How do they call each other? Or is Mantra in charge of calling them both separately, in which case how does the shading VOP know to associate these two things? I really appreciate any leads, this isn't a production thing I'm just super curious and spelunking around trying to make connections.
  9. GLTF animation import

    Send an email to support and have your name added to RFE #96785 !~ That way we can have this built-in in the future!
  10. Could it be that your diffuse limit on the Mantra ROP is too low? I'm not sure why that would come into play on a transparent material though...
  11. In Mantra, most of the single-lobe VOPs (PBR Diffuse, PBR Non-metallic Reflection, PBR Metallic Reflection, PBR Emission) have layer inputs/outputs so that they can be chained together with energy conservation. However, PBR Diffuse and PBR Metallic Reflection only have layer OUTPUTS. Why is this? What if I want to put together a shader where those nodes don't come first yet they are still balanced energy-conservation-wise? I feel like I am missing something simple in terms of layering here.
  12. GLTF animation import

    I don't think Houdini supports GLTF 2.0 (which I think is the version of the standard that added skeletal animation). Anyways, I can't find anything in the docs about it... https://www.sidefx.com/docs/houdini/nodes/obj/gltf_hierarchy.html Blender supports GLTF 2.0, maybe you can use it to convert to alembic then bring it back into Houdini? https://docs.blender.org/manual/en/2.80/addons/io_scene_gltf2.html https://www.sidefx.com/forum/topic/72189/?page=1#post-305584
  13. UV Flatten is all you need to do traditional manual UVs, it lets you draw seams and unwrap and pack:
  14. dof, circle of confusion

    super-necro, but to get the camera visualizations that were asked about you select the camera, hit enter in the viewport and hit "z" "o" and "f" to toggle through the focus and clipping visualizations... this isn't listed in the docs for some reason (just submitted an RFE)
  15. Ce Trivia

    Ah, that's right I forgot about that checkbox on Mantra ROP... otherwise those exports aren't exported... thanks! I assume you meant transmission and nested dialectric though, I thought dispersion didn't need any additional exports... (P.S. In the above network the Compute Lighting VOP is actually still exporting even when the Switch VOP isn't grabbing its input... so probably not the best test... to use JUST the Unpack Layer VOP, you would also have to pipe Ce into a Bind Export VOP) (P.P.S. You do in fact need to add a Layer Export VOP yourself if you want to use transmission... there were a few of these inside Compute Lighting VOP dealing with transmission and nested dialectrics. There was also one for dispersion, but this way seems to work without it...?)