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Found 290 results

  1. Hey guys, I'm facing a problem when I want to render my extended ocean. Mantra crashes during the displacement creation process, and I'm pretty sure it's not an hardware issue (Ryzen 2700X, 64 gb ram). The output mesh is pretty bizarre : I have a surface created under the mesh when it should be flattened and so there should be no surface here : I dont know what's causing this, but I'm pretty sure that this makes mantra crashing everytime. I tried using a grid instead of the mesh and it's working. I think that what's causing this issue is that when I simulated the fluid there was no particle under the collider and so it results in this weird mesh, I'll try to simulate again with a larger particle layer to see if it solves something. Here are the meshing parameters : I can attach the file if needed but as there are heavy caches that needs to be calculated it may bothers when looking for the bug. Cheers,
  2. I'm trying to create rings in mantra that are larger where my scattered points are brighter. I've got a setup that works for that, but what I'm looking for iis for the rings on top of each other and overlap one another. I figure I need to loop over my point cloud one point at a time and then multiply the result on top of each other maybe. I can't seem to figure out how to get a loop that does what I want. I tried to follow the documentation for the point cloud nodes, and it even mentions that a few of them are useful in a loop situation but it's just not working correctly. Is what I'm trying to do even possible. I don't have a lot of experience with mantra. mantra_pc_lookup.hip
  3. ocean extension tiles

    Hi! I have some issues with my first ocean extension. It shows with strange lines and repetitive patterns. I merged two ocean spectrums, add seed on these parameter and even try diferent numbers on downsample that belongs to material builder. Anyone can tell me what's wrong? thanks in advance. ocean_extension.mp4
  4. rendering problems

    Hello, I want to render and export my simulation as a video; however, the first time I tried to render it, it succeeded but I cannot save it as a video, the error statement was shown as the first screenshot; the second time I tried to use mantra and directly render it to disk, but it gave me another warning shown as the second screenshot. Does anyone know how to solve the problem, or what is the best way to export my simulation as a video? Thanks in advance!!
  5. hi, I try to optimize Mantra rendering. This example is about glass object, so try to apply for high sampling and more refract Limit. To do it, I attached render properties from edit parameter interface in a Geometry node, as a screen capture showing. However, a rendering image seems to ignore and nothing reflected by the parameters. So far; - pixel Samples and refract Limit are not working. - Geo Time samples is succeeded to overwrite. I wonder if I am missing something else, or actually we can only overwrite some limited parameters.
  6. Hello, I made a comparison between Arnold and Mantra renderer about vdb motion blur. Mantra works like a charm, but anyone knows why Arnold volume motion blur looks like this??
  7. Hi, i'am trying to instance lights on custom points that were created from geometry, but render doesn't start at all or rendering and loading a lot slower than standard primitive geometry and ram usage incredible high. If anyone can help, I will be very grateful Custom points https://prnt.sc/sz0fcl Grid primitive https://prnt.sc/sz0grm inctance_problem.rar Problem is solved, pls delete this topic
  8. Hi everyone, I'm trying to render vdbs with motion blur using mantra and arnold. With mantra it's working fine, but with arnold the motion blur won't be proper. I made a comparison. You can clearly see, something is not right. It became more obvious when I increased the velocity. The motion blur with mantra is excellent, but with arnold it became a mess. Do you have any idea what is happening here?
  9. Hi. Like my reference image, I used displacement for the green color. (From Shader) (viewport) (render image) 1. How to soften the edges. (The edge naturally?) 2. I want to add noise to the green color once more, like using a lava shader. 3. It's confusing whether I need to do what I want to do in the shader or in the sop. If you do it in the shader... Is there a way to visually check it in sop? I also attach my hip file. Please advise. Thanks in advance. noise_test_dis.hipnc
  10. Hello, everyone! I have a question about shaders. Like in the image ... It should shine like a lava shader. For example ... I want to give a feeling of shining from the inside. It's like seeing inside a ghost's body. I don't know if the explanation is enough, but ... Could you tell me what keyword to search for? Is it just necessary to adjust the transparency of the mantra shader? Thank you.
  11. Mantra Coat IOR

    Hi! I've been trying to replicate something similar to Arnold's coat IOR parameter in Mantra. Ideally I'd like to be able to control how much of a coat layer is visible depending on facing angles without affecting the underlying surface, even if this involves breaking the law of conservation of energy. Any ideas on where I could start? Thanks, Nathan
  12. fresnel in volume shaders

    Hi all, Because of the absence of deep control in the redshift shader, i'm trying to achieve what i want in mantra but dont get how to proceed. I'm trying to apply a fresnel to the density and emission of a volume. I tried just to multiply the density/emission with a fresnel node but of course it cannot be that simple I tried to create a gradient volume, converting it to camera space and feed it in the fresnel but no succes neither.. Any clue?
  13. Can anyone give me advice in rendering my water simulation? PLEASE WATER SURFACE CACHE is flickering for some frames! I attached image of 2 frames, first one is flickering and the other one is not. Just some of this frame has this problem and I have no idea what is wrong with surface cache. I rendered this water surface with glass material, and I've tried render with other material but it was same with flickering. And Surface_cache seemed fine with it's shape. Is it problem with Normal? Please let me know if you have any ideas. THANKS!
  14. Good evening everyone! I learned some lessons and trained at home in Houdini, and tried to make realistic fluids together in vials for honey and chocolate, other types. I looked at pictures on the Internet and carefully studied how to create bubbles, and tried to make mantra materials. but it’s not like photographs of real honey bubbles. I uploaded - a rendering image and a project HIP. Help me how to create materials correctly? hdri.rar honey_colorls.hipnc
  15. Hello! I have a few questions about rendering glass/refractive materials in mantra. I found more documentation for renderers like vray and arnold for getting good looking glass. Obviously the parameters are a bit different, but more or less they are very similar. Take a look at this photo about glass and vray from this articles: https://blog.turbosquid.com/2014/04/21/turbotips-v-ray-material-part-3-refraction/ For purposes of testing, I decided to create a similar scene rather then in my main project. That way I can work in a simpler environment and also upload my .hip here. My first question are: Many documentations/sites have the index of refraction (ior) for glass. The article above reads: "IOR is a very important parameter to set correctly, in order for your material to look believable. Fortunately, these values have been calculated for all sorts of materials, so there’s no need to guess here." It then states the ior of glass is around 1.5, which checks in with most other places. How can you just say the IOR of glass is 1.5? Wouldn't some glass have different IOR values? Especially if the glass is flat vs spherical or warped. If I try to match the ior values, it looks nothing like the vray photo. IOR of 1.5 is way too distorted to look correct. Please note that my sphere has an inside and a outside (thickness). I set the normals correctly. It seems having thickness to my sphere causes the ior to double. If I delete the inside of the sphere, it is less distorted. So I try setting the IOR to a lower value. However, once I do that, the reflection becomes too weak and super grainy. Mind my actual project is more complex and the reflections are soooooo grainy. Even with a pixel sample of 20 and turning up my light samples, its still too grainy and takes too long. So why can't I change the IOR for reflectivity separately from refraction? The manual says its not realistic, but its just not working for me when it is tied together. If you look at my photos below (you can make them bigger by clicking them) you can see that 1.5 distorts it too much. In my real scene, I have a snow globe. Whats in snow globe is distorted so badly with 1.5 you can't even see what it is. As I said, if I turn the refraction down to 1.1 or 1.2, I can barely see the reflections and they are SO GRAINY. I tried turning up pixel samples, reflection/refraction quality, the sampling on the lights, but its still way too grainy. Any thoughts/tips? glass_test.hiplc
  16. It's my first week using the apprentice version (build: 18.0.391) and I am having troubles rendering my files out in mantra. It seems that this problem is not unique but the available solutions are not working for me (like spacing in file paths, firewall issues, etc). I am still going my way through this but been not able to render my builds is really bumming me out since long time. Any leads will be appreciated. Thanks.
  17. Looking for some advice on rendering a smoke/dust sim with a heavy building destruction sim as a holdout using mantra. Without holdouts the smoke takes about an hour or so per frame as expected, but with the holdouts it is taking many hours (up to 6 hour) for some of the heavier frames. I am using packed alembic caches for each of the layers then merging them together and setting as force matte in mantra.
  18. 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.
  19. Hey guys, i have been reading all about Ray Tracing and Path Tracing, and i know what both of them mean, but i'm confused about certain stuff. Is Path Tracing an upgrade to Ray Tracing? Or is it is own algorithm that replaces Ray Tracing? and do we have it in Mantra or not? I know that Path Tracing mainly provides solutions to GI problems, is that already implemented in Mantra? I need some clarifications regarding this, Thanks!
  20. Iso Art

    Just showing some video art I had fun making recently. Pretty simple technically. Low res everything. https://vimeo.com/407189184 https://www.instagram.com/p/B-PX0ryDgB9/?utm_source=ig_web_copy_link
  21. HI My extended ocean have very high specular and I couldn't reduce it or ged rid of it. My lighting rig is Sky Light light, rendering in Mantra using the default ocean surface shader. I tried everything i know the specular is still there, even when when lights are off , I have turn off the "reflect lights" option, the specular is gone but I end up with a flatten not nice look.. Attaching frame example Thank you!
  22. Hello! I just got myself a threadripper 3960x for freelance simulation purposes etc. My workstation is now up and I'm doing some performance tests. I'm getting some very unexpected results when rendering in mantra. And I'm very curious if someone can help me understand what's going on under the hood? A simple scene I created(with some geo, lights and reflective materials) takes about 2 minutes to render in mantra in bucket mode. All good and as expected! The same scene takes about x3 times as long in progressive mode. If I monitor the core activity, they're almost idling while rendering, then suddenly, about halfway through, they all accelerate up to max speeds and finish the render in seconds... Anyone wanna take me to school? Thanks, Joachim
  23. I'm having a devil of a time trying to get rid of fireflies in a render (files and an .exr frame attached). I've isolated it to the direct reflection pass (the hotspots along the nose in the pic), and Nuke tells me they are way hot superbrights. Doing the usual Google fixes (working with diffuse limit, boosting reflection quality and overall render quality, &c.) haven't changed anything. In the scene I have three lights and surprisingly it's not the environment light that's causing the problem (I isolated the lights and also boosted the sampling quality on the environment light), but the key light (a spot light, but I tried distant and area lights with the same result). This is my first time dabbling with Substance Painter, which I used for a quick not-too-boring look, and it looks like the problem might be with the roughness or metallic maps. They're .tgas, and open fine in Photoshop. If I turn off all maps and boost the roughness the hotspots are less hot and spotty, but I don't think that's actually causing the problem. I'm sure this is something easy and stupid. Thanks for any assistance! (Credit where due: the original bust is from a photoscan by Ryan Baumann on Sketchfab.) caligulaFireflies.zip
  24. hey guys, do you know if it is possible to use intrinsic information in a shader? something like intrinsic:indexorder in a render state just like with packed attributes. also, still in a render state, packed:primnum or packed:ptnum doesn't seem to be working. if i make an attribute in a wrangle on packed prims, let's say i@primid = i@primnum, and i call that in the shader with a render state it works as expected. any idea? thanks Martino
  25. Shading Theory with Karma

    I'm happy to announce that I've teamed up with SideFX to release a new free course! - Shading Theory with Karma. These videos are designed to teach you the fundamental ideas behind shading/texturing while utilizing the principled shader, karma, and my dear friend - Shaderbot. Visit CG Forge to download shaderbot along with access to the videos for free. https://www.cgforge.com/course?courseid=shadingtheory Have a nice day,
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