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About Butachan

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  • Name Nicolas

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  1. Hi guys I recently created a free asset to test shaders in a consistent environment regardless of the scene I am. I am kind of old school and feel a consistent shading testing area is very comfortable to create different shaders. The idea is that no matter what complex scene you are in, you can just bring this asset and then test render shaders on a tri light set up with background and env. light. The asset itself is very flexible. multiple shapes test, and grid or plain background. You can even bring your own object or shader ball into the scene. You can find the asset here: https://www.orbolt.com/asset/Butachan::nh_shadertest::1.0 Please read the instruction as I made the asset object, light camera, and actually everything invisible in the scene so it doesn't really clutter the scene you are working. I also made it open because as it is a render related asset I feel it will need some tweeking here and there to adapt to your needs. Bests, Nico.
  2. I just made this file at work (sorry I don't know if you will be able to open it). But doesn't really use anything unusual. Basically you create an RBD sim and then deactivate the sim at a particular frame. you activate on that same frame and create the FEM object. If you want you also create a switch that changes the model from the RBD object to the FEM object simulation. This may be not the most elegant solution. But the idea is to play with creation and activation frames. Also this system will not transfer velocity or anything to the FEM solver. I am sure that there must me a better way to do this if you need to but like I said it depends on the necessity of you r project. Best, Nico. RBDtoFEM.hip
  3. I'm not infront of Houdini, but inside the DOP network in the object creation node you have a creation frame. you can choose then the creation of the FEM object at a particular frame. Sorry I cannot be of more help.
  4. The set up will probably change according to what you need. Maybe you can be more specific about what you need your object to do. Basically if it is just an inert object that suddenly explode (exploding brains for example) you just simulate that moment. I am sure that is not what you need, but be more specific and maybe we can help.
  5. Is there a way to make the transform parameter on my subnet or HDA appear as a transform handle in the scene viewer?
  6. Thanks very much for the answers. I am definitely less confused about GI in houdini now. I think in the last builds I couldn't get the all path tracing method to properly calculate caustics...I had to use faux caustic but like you said its good enough so I didn't mind. I will sometime do a test and send a bug report if in later build the PBR is actually not going through all paths as it says the setting. 1.- I will definitely try to avoid using photon maps as much as possible. with moving object they tend to be a natural enemy. 3.- Will have it in mind...now with the posibility of render in a render farm is nice to be able to have that option without the need to buy arnold. Can you do this on a per object level? basically change the shadow intensity projected by one object rather than all shadows from a light?
  7. Hi! I recently fully committed myself to Houdini from C4D. Mostly because my first love in 3D was Softimage and when I met houdini was like....but I digress.... I have a few newbie questions that I will greatly appreciate if a more experience user answer them with some honest advice: 1. Very confused about GI: Is Indirect Global photon map the GI solution for houdini. or the PBR mantra render with multiple diffuse bounces is also capable of GI simulation. I ask because the last time I used GI with photon maps was in lightwave with montecarlo calculations (also a bit in C4D before the physical render was implemented) and I remember the horrors of the flickering and bloches and etc etc. So it really scares me to have to go back to photon maps. I am particularly confuse becaused if the PBR rendering is not simmulating GI. What means diffuse bounces? why Env maps HDR actually illuminates the scene....A clarification of this will be greatly appreciated. 2. glass and transparent shadows: In most render engines I had used refractions produced transparent shadows. In mantra it seems that this is called (appropriately, I must admit) faux caustic. This solution is quite good enough for me. But 80% of the time I just want the semi transparent shadow, not the higlights and other details caustic cause. Is faux caustic the only way to go in this cases? 3. And an important question that I am honestly asking as a newbie with no ulterior motive: is one of the answer "use Arnold (or insert any other renderer)" ? I actually really do like Mantra, the shading tools, noises and integration of custom parameters encourage me. I also mostly do motion graphics, some VFX but nothing that push me to look to an ultra-realistic render (read Arnold). But a good enough GI solution (kind of C4D physical renderer) is kind of very useful. Sorry for the lengthy post....oh crap I just made it longer!
  8. Yes, it seems there are a lot of redundancies and errors going on there, probably because of the change to PBR rendering...but my story i think is quite particular as...somewhere between build 607 and 673 they change the way faux Caustic works and the problem with over exposure doesn't exist anymore. but the ALL path solution suddenly doesn't work! The result is the same now and finally I have proper behavior on glass. I was about to start to build a proper library of materials in mantra....this first step did not make it easy :/ To be honest I am suprised this didn't come up early....
  9. Hi! Yes the Faux caustic seems to help but in reality caustic is a completely different phenomena and it will cause the entire refraction to be exposed (Capture 3). But I found the actual solution under the Mantra Rop in shading setting allowable paths to ALL PATHS!!! I don't understand why on earth this is not so by default! This do raytrace the glass properly. Updated to latest build and now I have problems with the refraction again even after applying all paths will fill for a bug report.
  10. I don't understand why I am getting this weird black surface on all objects inside a glass shaders??? Please any help will be appreciated. test render.hip
  11. Would you mind sharing the file? this problem seems interesting .
  12. Sorry Eetu, I didn't really save any tests. However the sims are fast so I will put something together and render a flip-book and PM you some drafts. Though I will probably not use as many particles as the vid sim, but forgive me if it take me a while (quite busy at work now). Also this was mostly for practicing particle forces creations so I kind of want to move on to the next experiment I was very inspired by a speaker from animal logic. The volume acceleration structure sounds very interesting. But I really just used point cloud system the same way pop-interact does it. By the way I just saw your lab, very interesting stuff in there....I see post like your lab and it makes me want to play more and more with houdini.
  13. Thanks! I calculate the gravity pull for all particles in relation to the sun, but I optimize the force each particle exert to each other based on distance and max number of particles (pcopen). I also added to this force a chance for the particles to absorb each other based on their scale when they touch.... gaining and losing scale and mass appropriately. which in turn affect the force it exerts on other particles...this is actually where the sim became interesting because a changes on this values produces quite different results and looks, I also think this is the part that could be polished the most. I actually made the distance exponent in the gravity force exposed and you can get quite interesting results playing with it.
  14. Hehe, Thanks. And someone else mention the same thing in the sideFx Forums (LOL) I will have in mind my definitions next time . For now I was concentrated in practicing the forces and interaction between particles.
  15. https://vimeo.com/188376689 Hi guys, I posted this on the SideFx forums but I also wanted to share it here... Basically, after the webinar on particles I felt inspired on creating my own galaxy system. The objective I put my self was to create a space opera style looking galaxy. But the real aim was to create the working forces behind it. Basically a system that can define the sun or suns, the initial speed of the traveling space objects and the gravitational pull forces affecting all of them. Also I added a particle absorb relationship, some big particles will gradually absorb the mass and size of the smaller ones, making themselfs more massive and bigger. I feel there are some quirks to polish but overall the core of the system is already there. Everything is based on real physics, or as close as I could get without making it super heavy. And indeed the results varies dramatically (in a good way) acording to the parameters input on to the forces, basically mass of the sun, of the debris around, distances, and initial speed. It was a fun excersice! maybe I will revisit it one day.