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Everything posted by lazza79

  1. Hi Guys, I am preparing a new scene in Houdini and I need to track the video first. I made both reference images and video feed (4K) with my iphone 7 Plus. Does anybody know what's the sensor size and focal length of both video and photo cam? (the wide one). I am finding different values on internet and I wonder if anyone has done this before and if anyone knows where to find such information. Thank you! Cheers! Lazza79 P.S.: I already tracked the video but the data came out from the tracking software do not match the data I found on internet 8.03mm focus and 0.95x0.53mm for the video camera. The focal length of the lens (according to the EXIF of the pictures) should be 3.99mm, not 8.03...
  2. Question about tracking

    Thank you Atom, I know I have to undistort the plate, but that's the easy part and the distortion algo is pretty good. I am using 3DEqualizer to do the track. I used it and tracked several videos before but always using footage from my Canon 60d. This is the first time with iPhone7. I wanted to use iPhone because the video footage is much much better than my Canon's.
  3. Hi Guys, I am trying various solutions in order to destruct a building. I would like to use a deformed sphere for the main esplosion on the base and I would like the building to collapse after. I was trying to use the color to break some constraint but in order to do that I need to keep "overwrite with SOP" active in the glue network. By doing that, the whole glue network is recreated every frame and the wall is not broken by the sphere. Could you please help me? Cheers! Lazza79 P.S. I also tried not to use the glue but then I had problems in creating the particles for dust and grit. Anyway, any advice is appreciated. church2_destruction_odf.hip
  4. Help with destruction

    I think I found out how to do it: I used an Object Merge inside the sop solver in the DOP and transferred the color from there. This is the result, obviously there is much more to do, but I am happy that I found a possible solution... Any advice on the better practice for destruction is appreciated anyway... Cheers! Andrea untitled8.mov
  5. Hi Guys, I noticed that my simulation generates some "string-like" agglomerates of water that act weirdly. As you can see in the video and in the screenshot, these strings are generated and they remain almost intact until they fall together. I would expect them to separate or act in a more "random" way... Is there a way to avoid the formation of these effects? How can I prevent/limit them? Thank you for your help! Cheers! Andrea untitled.mp4
  6. Hi, I cannot understand where these velocities are coming from. I am trying to rise a sub from the water and I am doing some research. I tried to simplify the scene and I found out that I have some velocities in a part of the volume that, in my opinion, does not have "full" voxels Please see the attached image and hip file. I am using a static object with volume proxy as a collision volume. If I remove the viscosity attribute of the FLIP fluid, the velocity decreases dramatically.. Where I am mistaking? In my opinion, the "red" velocities should be only where the volume has the "full" voxels and not in the whole volume... I apologise for my ignorance but I am still learning Thank you guys! Cheers! Andrea sub_odforce.hip
  7. My friction is also quite high...
  8. Sure! Find the setup attached. sub_tests_AL.hip alembic_sub_anim_3.abc
  9. Unfortunately I am still having these strings. Can these being caused by having set surface extrapolation to 0.7 (default 0.5) and velocity smoothing to 0.5 (default 0.1) ? My sim resolution is 0.065 and tank is 42x68 I see that Igor's part sep is way higher than mine (0.15) so I think my problem is elsewhere Cheers, Andrea sub_v21.mp4
  10. Thank you Zybrand. You can see the speed of the submarine in the video I attached in my previous post. The sim is in fact low res 0.08 because I am still in the set-up phase. What you mean by playing with the droplet detection? Right now my droplet setting are the default ones ( min 0.5 - max 1 - blend with fluid - velocity blend 0.2) Anyway, right now I am re-simming everything since I have raised the velocities on the lower front part, in order to have more forward-oriented splashes Cheers! Andrea
  11. Simulation scale

    Hi guys, I have another question for you, this time about scale. In some of the tutorials for FLIP fluids I've followed, they say that it is important to keep the scale of the simulation as close as possible to the reality. In my case, I have a boat that is 100 meters long, should I try to scale the sim 1:1 or can I scale it down of half or 1/10th? How should I change the solver's spatial scale and mass scale? My main doubt is: should I use a 150m domain with bigger particle sep or a 15m domain with much smaller particle sep? Thank you! Cheers! Andrea
  12. Simulation scale

    Thank you fathom. So I really need to upgrade my pc to 64gb of ram (right now I have 32) Cheers! Andrea
  13. Simulation scale

    Hmmm, not really because obviously in a smaller domain I will boost up the particle separation, hence the running speed should be the same... Yes, 1 houdini unit is 1meter. I already have the animation for the boat in the matching scale, I just need to decide how to run the sim. Right now I am using 0.03 separation in a 1/10th of scale. I scaled down the gravity as well but I didn't touch the spatial scale and mass scale. Thanks, Andrea
  14. Hi Guys, I am literally running out of space and I would like to ask you a question: During one of the workshop I followed, the tutor suggested to use the extension "bgeo.sc". I previously used "bgeo.gz". Does anybody know which one is the best and why? Cheers! Andrea
  15. Compressing methods for caches

    Thank you guys!
  16. Alembic to VDB

    Hi Guys, I am trying to export from maya to houdini using Alembic. My problem is that I cannot succeed in converting the alembic geometry into VDB (and then convert it to volume) in order to use it for a particle simulation. The VDB from Polygon I use takes ages to process... Can somebody help me? I am not even sure I am exporting it correctly from Maya. Attached you can find the file and the original Maya source scene. Thanks!!! Andrea Archive.zip 688_sub_03.ma
  17. Alembic to VDB

    Thank you Dennis, I am still learning Houdini and I was confused. Cheers! Andrea
  18. Hi guys, I was trying to achieve the "evolution" of my waterfall/river scene by making the water to destroy a wall but I have a problem with the constraints: the wall starts to collapse way before the fluid reaches it and the cause is that the constraints are broken. I made this small hip file to test a similar scene in a smaller scale but I still have the same problem with the constraints: right now, as you can see from the file attached, at frame 2, all the glue constraints of the wall are broken and the wall starts to collapse. The way I would like to achieve this it would be to have the wall as an RBD object (or fractured object, still don't know the difference very well) and the river bed as a static object (to which the wall should be constrained to). I watched the bullet masterclass but with no help on this matter. Can you guys help me? Is this the correct way to do this? Why am I getting those huge forces on frame 2? Is it due to the gravity? I am sure that the solution is easy, I am convinced that I just lack some knowledge... Thank you for your help! Cheers, Andrea constraint_test.hip
  19. Problems with constraints

    if you want, you are more than welcome (hip attached). Today I was trying to change a setting in the FLIP object, setting "use volume velocity for collisions" instead of point but the result is the same I wonder if we should use something that can transfer the velocity from the particles to the wall (advection?) but I don't know how to do it... I can see that the particle pass through the wall but they don't really push it. Actually it looks like they are pushing it vertically... Thanks! Andrea week03_AL_waterfall_e.hip
  20. Problems with constraints

    Hi Blayke, proceeding with the implementation of my test scene, it seems that the particles are too strong and they provoke a lot of "jittering". I tried assigning to the wall a higher density (even 4000) and lower (700) but with no significant improvements. Maybe I should try assigning a mass to every piece (primitive)? Ideas? Cheers! Andrea
  21. Hi guys, I was working on a simulation and I had a lot of problems with my houdini for Mac version 14, 15.343 and 393 (downloaded when it was a daily build, now I see that is marked as "production"). The problem was inside the simulation "dopnet_rbd", with "concave" setting as a geometry representation for the RBD object. Playing with the voronoi fracture settings (cusp interior and exterior objects, create inside surface and connect inside edges) Houdini crashes when starting the sim. Does anyone has my same problem? There is something I can do or something I do wrong (for example some rules like: you can't use concave toghether with <this> setting...) In my opinion it may be something related to the video drivers but it's just an hypothesis Thank you for your help. Cheers, Lazza79 week03_AL_waterfall_c.hip
  22. Unfortunately I did not resolve the problem and I am not sure on what generates it. I had a crash, and from that moment I cannot run my simulation anymore (a different file this time). I am almost sure that is a problem related only to my machine (I tested the file on windows and worked) but I don't know how to solve it. I reset the SMC and the NVRAM but it didn't solve the problem. Maybe is not related with the video... Any other ideas? Cheers! Andrea EDIT: Proceeding further it seems that the problem was related to the temperature, but not sure. This is what I did: I downloaded a tool to push the fans to the maximum RPM. Meanwhile I recreated the DOP network step by step and it was working. Later on, I tried the same DOP that was freezing and it worked correctly... This makes me think that the high temperature prevent the mac to work correctly and somehow "stopping" Houdini since it was asking too much resources.
  23. Problems with constraints

    GREAT!!! Using your method it's working! Now I have to better understand why my method didn't... Anyway this is the result (for now) looks nice (attached). Thank you so much!!!! If you happen to be in London I'll buy you a beer!!! Andrea test_breaking.mov
  24. Problems with constraints

    Thanks Blayke! unfortunately I tried to follow your advice but still doesn't work. I tried to cookie out the wall - the terrain and I even moved the wall up by a tiny bit (0.1) to be sure it won't intercept but is still exploding. Ah, I also set the feedback to 1. This is the updated file, obviously you can edit it or put sticky notes in it... whatever you prefer! Cheers, Andrea week03_AL_waterfall_tests2.hip
  25. Problems with constraints

    Thank you very much for your helps guys, I appreciate it! Proceeding with my scene, I have another issue that I cannot still figure out: I am trying to simulate a fluid destroying a wall. The problem is that as soon as one particle hits the wall, it explodes! I tried to dial down the velocity scale but with no success. Any idea? I am attaching my scene... Cheers! Andrea week03_AL_waterfall_tests.hip