henrik.g

Hey everyone, I am trying to wrap my head around Bullet some more and wanted to clear some questions, so i'm solid there... 1.Units I: I found this info on the web: "A 12 pd started with a muzzle velocity of about 1769 Feet Per Second " If I was to set this up: Then Mass would be 6 and Initial Velocity would be 539, correct? 2. Units 2: If I would want to compute Mass - and lets assume Iron - then I can just check in with Wolfram Alpha and use their 7874kg/m3, correct? 3. Units 3: Glue Strength, is there any "real world" counterpart? Or a formula that describes whats going on, or is this just artistic choice? 4. Settings: Bullet Constraint Iterations: This seems to have an massive impact on the outcome, is this normal? 5. Workflow: Is Object-Merging within the same SOP acceptable? I think with all these connections from left to right is kinda cluttered...? This all leads to my HIP. I have 2 thin sheets of "concrete" or whatever and want a sphere to pass through, yet what ever I do, however low I set Glue Values and so on, everything will collapse, but the Sphere wont pass through? Is there anything I got wrong?? Thanks for any help! Best regards! cantPassWall_v02.hiplc

Hi Dennis, Olivier did not want to see your scene to judge it. No one is judging here, we are all learning from one another. I think it should be possible to get a harder holding effect, yet, if we cant take a look at your network, we can't see where a possible problem within your setup lies.

Outstanding work! I really enjoyed the colorful, playfullness on some of these! The paper planes or Honey Pot! Inspirational!

Maybe add a ramp parameter for the width of the rendering and let it fade out smoothly at the end? For the sides blur the alpha only in Comp?

I guess the fluid feel here comes from the thickness and the blur of the lightning effect. It is not razor sharp as basic rendering would create. So I would try two things: - try to just a little bit smooth out your lightning - play with blur, Glow, timeshift in Compositing - I am pretty sure compositing makes this.

http://david.li/ awesome stuff

If your Image Sequence for example as been retimed and starts at 1001 then your Houdini Timeline has to correspond to that. In the lower Right corner you can set the beginning and End of the timeline.

Does your timeline have the same timecode as the image sequence? Also take a look if Houdini did not by itself reverted this to a single Digit. This happens to me sometimes, I just witch it back to $FX again.

Hey everybody! Im not sure if this shoukd have gon to the rendering sub-Forum, but... I have a Scene with a Wall in the back, where I have Wall Impacts, No I am projecting the original Image on the wall and have it render this. This looks fine as a simple Render, but essentially I definetly need more control in Compositing. Is there a useful way to seperate the moving pieces, aka pieces that are not glue constrained anymore, form "the wall" ? I tried doing this by grouping with "abs($VX)+"abs($VY)+abs($VZ) > xxx) This kinda works together with a clipSOP, but I get some flickering pieces because those falling later are on the bring of this Threshhold. If I get the Threshhold to low, I have larger wall pieces pop in. Can anyone give me a hint in the right direction? I thought maybe I can get an Attribute for all Glue Constrained pieces and delete them? Something like that? Thank you guy soo much! Best!

Great Info there dan.! Thanks!

Bump?

Hey everyone! I am in the RnD Process of having a bottle filled with water crash to the floor. I have set up the Bottle with Bullet and constraints. Which works fine. Also the FLIP Fluid without Bullet works fine too obviously. Now if I merge the whole stuff the first few frames mostly work well. But the moment the bottle crashes to the floor the Bullet Sim kinda gets horribly explosive. I tried different flip collision method, yet they do not pick up the very thin bottle geometry. Any ideas on how to make this work properly? Or should I just sim both things one after the other? Assuming the water would not have an massive effect on the behaviour of the Glass? Thanks so much for any help in Advance! Hipnc attached. WaterInBottle_003.hipnc

Please correct me if I am wrong. 1. You can’t. As those are volumes, you would end up with very strange results. If you want the Motion Blur. Render it. Pump up the Xform Samples. 2. Smoke and Fire Mask are not vector passes but float passes. Nuke kinda does not like them and brings them in as „other“. The „s“ channel is your SmokeMask. „f“ your fire mask. 3. Try the Micropolygon Engine. It works fine with volumes. 4. There are possibilities on the Shader. There is a thread around here on the forums, but I think the general agreement was kind of: dont. It just not necessary. 6. Thats a seperate render. Add a seperate shader and Set the color to white. Add 3 point lights as red green and blue. Maybe turn of any volume Lights you might have. I hope this helps and is mostly correct.

There is the Sapphire R290 Vapor X version which holds 8Gigs. I was thinking this could help with doing RnD in rather Low Resolutions. Not rendering but Simulating using OpenCL. The OpenCL support is afaik better on the AMD side than on the Nvidia Side of things.

Yup. As of now it works fine. I played only a little bit with the whole GPU acceleration for fluids. So I cant really say anything about that. Most of the Stuff I had to do needed mor ram than the 8Gigs that come with the card… If you have any specific questions I am more than happy to reply.