Marcocheng

correct. Since i have pre-roll in my sim, you definitely need to copy your creation frame number into rest field offset.

Thank you Tomas. Prehaps starting frame not equal 1 causing the empty rest field result? PS:emm i found offset the rest field works fine, thanks again!

Hello folks! I'm currently playing with pyro with volume displacement (Arnold), i have to convert my volume into vdb so that it can rendered with Arnold, i plug the convert VDB after my volume cache, rest and rest2 field turns zero. I wonder what causing that. I'm working with Houdini 16.5. Convert VDB sop remains default value and parameter. Before convertVDB: After convertVDB Hope for an anwser! Thanks! Also if there is a way to combine each scaler field into single vector field? thanks again

Hello Mangi, Wow, that's a very detailed test. Thanks for spending time on this first of all. I've actually tested the render with AOV output (diffuse + specular pass), the flickering seems to happen in the diffuse ray as well (while the specular pass is black when I switch off specular attribute in Arnold shader)... I'm not 100% sure the flickering was caused by the specular... And yes I'm a v16 user... I don't know if they upgrade the standard shader in v17 (both are arnold 5 right?) Please to have more info with that! Seems to disable specular and increase light sample might help... regards Marco

Post the file otherwise we hard to follow the problem... btw if not, try to you volume vop to increase the contrast of the smoke sim and run the POP again

Here's the file, just load the animation in it... and cook the rest. Have a nice day. Animation.7z GrainFirstEverTest_v001_Publish.hip

Hi, I crop out some of the particles by using a group node (by a geo) and a delete node to reduce cache size (that's why some of the particles seem to disappear when they reach the bound), the cache cost 16GB of space, let me upload the source setup HIP and you cook all the node. Sorry for the confusion Cheers

I think the camera angle also matter to the flicking issue. You will get less flickering while grain facing the camera. But when the grain is larger facing angle to the camera you will definitely get more flicking. (random dots flicking) To my instinct, it seems like a pixel filtering issue... Flicker.mov First: Grain facing the camera Last: grain isn't directly facing the camera (larger facing angle). Edit: More test today. I render several AOVs out for debugging and increase the directional light sample from 1 to 4. It doesn't help, and the flickering appears in the direct diffuse layer. Flickering_DiffuseDirect_4LightSample.mov

Hello Mangi, I just upload a simplified scene file and cache in the top post. I crop out some of the particles to make the file more lightweight but the grain and light rig are definitely the same. Only one thing you need to do it yourself is to replace the dome texture. I have tested the scene render again and found the flickering area is basically focused on the direct light area (the grain inside the shadow area gonna be fine). I've try to fix the sample seed to 100 (fixed noise pattern) and remove the indirect specular blur but seems not working... I've seen all two video you made and there isn't obvious direct lighting so that may be the reason you don't have the problem. Check my files or add a direction light like sun. But thanks for spending time to test it anyway. Big thanks! Have a nice day Marco

（）Hello folks! I'm testing grain shading in Arnold 5 in Houdini 16.0. The simulation was bad just for the test purpose anyway. The top surface starts flickering during the rendering. And the rest area (side) is fine. When I apply a sprite to those grain particles there isn't any flicker during the playblast (see the playblast video). But when I use Arnold render to render those particles, the flicker starts to show up on top of the surface. So that might be a rendering problem (see the rendered video)... Render: FirstGrainTest2_Flickering_H264.mov Playblast:PB_Flickering_H264.mov Spec: Particle: 1,085,000 Shader: Arnold standard surface (no fancy tweaking just by default with custom ramp Cd) Pixel Filter: Gaussian with size 2.25 Sample: 4/4/2/0/0/0/10 Noise seed: $F Raydepth: 1/1/1/1/0/0/ Low light threshold:0.01 motion blur keys:8/8 What am I missing here? Thanks！ Note: I create a simplified scene with cache file attached. The reason is the original cache is simply too big to upload here (20GB, around 100 frames). The simulation cache is the same as the video one, I just crop out part of the grains. Good enough to show the problem anyway. The shader and light rig is the same as the video above, you will found not fancy stuff TBH... Maybe you need to find an HDR as well... File: Pure file：Arnold_Grain_Demo.hip Cache: Cache.7z

Oh seems the pack edit cause the problem... thank you! You made my day

Hello folks! I'm trying to make a wood fracture with a bullet sim. I fracture the object with boolean then set-up a basic bullet solver. Everything goes perfectly until I add glue constraints. I use connect adjacent pieces as usual, then when I load it with glue constraint relationship and play the simulation, Houdini crashes. Without the constraints, Houdini doesn't crash... My Houdini is 16.0.736 (stable version as Houdini official), Here's the source file... Thanks! Marco Wood_Fracture.Bug.hipnc

Emm... seems this method cannot mix with constraints network... because the constraint is not able to detect impact

I've checked concave... it doesn't have any issue, but this is not practical...

Hi there, I'm currently trying to make some wood piece fracture simulation, and there is some weird result... After debugging, I found the generation of convex hull is the problem of my simulation... I use boolean fracture in this case and the explode view just look fine. But when I import the pack geo and see the convex hull, there are some weird hole and shapes. Any reason for this to the creation of wrong convex hull? Any tips are welcome! thanks everyone! Convexhull_issue.hipnc