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Showing most liked content on 12/31/2017 in all areas

  1. 2 points
    Howdy my dudes, I've been taking at a stab at building out a "portal" type shader for a few days now, and I'm pretty stuck. To elaborate, the goal is to basically to render from a second camera onto a texture (or render buffer), and then project it onto a piece of geometry to be rendered like any other object. Thus creating the illusion of looking into one portal, and out of a second portal (just like the game Portal). I've already solved rendering from the perspective of the other camera (I think.... I basically rebuilt fromNDC() in /mat/), however I'm currently stuck on how to project it properly back onto the geometry. Let's define the current render camera as "CameraA" and the second, portal camera as "CameraB" for ease of explanation. The issue that I'm running into is that the method I'm using requires me to sample the rendered scene from CameraB, as a texture. The reasoning being, that we need to clip the texture to make sure we're not looking at a squashed scene, but rather a scene that's clipped by the bounds of the portal geometry. However as far as I'm aware, there's nothing like Unity's render targets in Houdini. You could argue that, that's the purpose of the Render COP, however it's far slower than just shooting more rays into the scene from CameraB. Mestela sent me this lovely video by Roman Saldygashev in which he achieved the effect in mantra, so i know it's possible. For even more context, I've been following along with this post by Tom Hulton and his implementation in Unity, http://tomhulton.blogspot.com/2015/08/portal-rendering-with-offscreen-render.html Though in the attached file, I don't include the camera matching transformations he describes, let's just focus on the portal rendering.... I'm going to attach my test file to this post so all the smart people here can rip it to shreds. Please let me know if you think I'm totally approaching this problem incorrectly as well, as shader math is certainly not my strongest skill... If anyone has a link to the "Stupid RenderMan Tricks" pdf that inspired both Roman's effect and Tom's effect, that'd be incredible, because all searches on my end have turned up empty, so i'm kinda just winging it right now. JR_PORTALS_v004.hipnc
  2. 1 point
    Hi everyone, Just wanted to share a little something I worked on yesterday. I created a VDB creep within a solver and for now the issue I have is birthing points at different times and adding them into the solver. For now they all get created at the same time. Still trying to figure this part out https://vimeo.com/249245842
  3. 1 point
    Yeah, sometimes I like to watch paint dry too. (especially when I'm paid by the hour) Here is an example scene that demonstrates lighting with only material emission. There are no lights in this scene. The shader uses a RaySwitch to decouple material based emission from incandescent emission. This allows you to overdrive incandescent output while not blowing out your diffuse. You can even choose an alternate color for the incandescent light as shown in this scene. The sphere emits RED but the incandescent emits BLUE. ap_rs_light_by_material.hiplc
  4. 1 point
    You may have accidentally changed an internal HDA definition. I did this the other day and got a similar message. The solution for me was to simply delete the new definition in the otls folder under the Houdini 15.5 folder which shows up under user documents on the system. example C:\Users\YourUserName\Documents\houdini15.5\otls. Close Houdini and move the otls folder to the desktop. Launch Houdini and see if the message goes away.