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Everything posted by michaelb-01

  1. Grains - Disable Constraint Averaging

    I posted this on the SideFX forum but haven't had any response so I thought i'd try my luck here: I'm getting some unbalanced forces when using grains, its the same problem as described in the grains masterclass around 32:50. As Jeff says the solution is to disable constraint averaging and then insure all the internal forces add up to 1. I've done this but I still have an imbalance.. I wanted to check which forces are meant to add up to 1, in the video it implies that Internal Collisions + Clumping + Explicit Constraints = 1. However in the help document it mentions that Friction with Particles should be included as well. So should I set Friction with Particles, Internal Collisions, Clumping and Explicit Constraints to 0.25? (
  2. Grains cloth - bend resistance

    Using grains for cloth is extremely fast but since it’s not a fully fledged cloth solver it lacks control for creating realistic cloth sims. There is only really self collision and a basic stretch resistance through explicit constraints (through to avoid stretch you have to put constraint iterations very high..), but it doesn’t seem like there’s any concept of bend resistance in the explicit constraints. Does anyone know of a way of creating bend resistance or faking it somehow?
  3. Grains cloth - bend resistance

    Thanks for your reply Jamie. Yes thats similar to what I had in mind but would be a fair amount of work.. Obviously cloth does all this but its much much slower and I always revert to nCloth instead.. But when you have very high res cloth geometry and collision meshes (especially animated) Houdini's cloth is too slow and nCloth can't handle that amount of geo so i've been looking for workarounds. I had thought of adding another layer of grains but not ideal as it will slow it down a lot and there is not much control..
  4. Grains cloth - bend resistance

    Hi Chris, That makes sense, I suppose thats the best approach for getting bend resistance with grains, thanks for looking into it!
  5. Grains cloth - bend resistance

    Hey Alvaro, I think (though I may be wrong) increasing the simulation substeps (and/or the constraint iterations) will effectively increase the stretch resistance (so make it stiffer in that sense) but it won't have any effect on how much the grains (cloth) can bend
  6. Granular Sheet - Pin Constraint

    If you just want to freeze some particles you can use the ‘stopped’ integer attribute. If you want to animate the pinned particles you will need to update targetP in pops (as has been mentioned above). I’ve been doing a lot of ‘cloth tearing’ recently with grains and it requires a bit more of a setup but it’s doable. Essentially you need to: - prefracture the mesh - store a class attribute on the points (that will get picked up by the grain source) - for your constraints, in a primitive wrangle, check the two primitive points (using primpoint function) and compare their class values, if they are the same the constraint exists ‘within’ a fractured piece so we set its strength attribute really high (1x10^8 for example), if the class value is different you know the constraint connects two different fractured pieces so we want to make it tearable, so set the strength much lower (maybe 0.5) - enable break constraints on the grain solver and tweak the break threshold until you get some nice tearing. Post sim: - use a point deform node to drive the mesh by the points, but we want each fractured piece to be driven only by its corresponding grains points otherwise the mesh will stretch. You could try doing this in a for loop but that is very slow so I think the following is better: - time shift the mesh to frame 1, offset the point position by the class value (@P += i@class) and feed this into the first input of a point deform - time shift your grain sim to frame 1 and offset it by class too (it should line up in space with the mesh), and feed that into the rest input of the point deform - feed the animated grain sim points into the template points input of the point deform - if done correctly the mesh should tear cleanly with the points. To get a nicer tear there it’s actually a bit more work to be done, I’ll try and upload an example hip file if I have time. Maybe someone knows of another method?
  7. Just curious if anyone has recreated fStretch or similar a volume preservation method inside Houdini? fStretch - Softimage version - Are there any papers on this sort of thing?
  8. FLIP smorganic/sheeter effect?

    Cool, thanks Alejandro!
  9. FLIP smorganic/sheeter effect?

    Hi @Pazuzu, how do you think H16's new surface tension compares to your technique?
  10. Bullet collision ignore

    the "collisionignore" point attribute works when it is ignoring static RBDs, however it doesn't seem to work when ignoring active RBDs.. is this a bug?
  11. Custom PC build advice

    Hi, I'm looking to build a PC at home and I don't know a huge amount these things so I'm looking for some advice. My budget is around £3k. The main uses will be Houdini, Maya and Nuke. I do a fair amount of heavy fx work and I'm planning to do gpu rendering with redshift. My main questions are to do with which cpu and gpu to go for: CPU - the AMD threadripper looks very interesting, is it worth waiting to see how much that costs and how it compares to intel i7/i9? - are the i9 chips worth it? - or is it better to go for a dual cpu (e.g. dual xeons)? Would that fit in my budget? is it possible to use just one cpu on a dual socket (with the option to add another at a later date)? GPU - I would ultimately like to have 2 or 3 gpus for rendering but, so I guess this influences which motherboard I can get (with enough pci-e lanes) - I think the 1070 seems like a really good option to start with for price/performance
  12. Custom PC build advice

    I know but for the nodes that are multi-threaded, it should use all of the cores? There's no cap on how many cores it can use?
  13. Custom PC build advice

    also, houdini will definitely utilise all of these cores right? Even with windows?
  14. Custom PC build advice

    glad to get your seal of approval Marty
  15. Custom PC build advice

    Now that threaripper is almost out and its still looking good, this is pretty much my final parts list. I've gone slightly over budget (by £600) but I've trimmed it down as much as I think I can (though if there are any areas that don't look worth the price please let me know!). I wanted to run it by you guys one last time before I take the plunge! Please let me know if you spot any potential issues or areas for improvement. Thanks! (A couple of things - I'm getting 64GB of RAM for now with the view of upgrading to 128GB later, but maybe when DDR5 comes out next year! PCPartPicker says the Noctua cooler is not compatible but i'm planning to get the threadripper version of that cooler that was recently announced) PCPartPicker part list: https://uk.pcpartpicker.com/list/cf2zVY Price breakdown by merchant: https://uk.pcpartpicker.com/list/cf2zVY/by_merchant/ CPU: AMD - Threadripper 1950X 3.4GHz 16-Core Processor (£979.99 @ CCL Computers) CPU Cooler: Noctua - NH-U14S 55.0 CFM CPU Cooler (£51.97 @ Amazon UK) Motherboard: MSI - X399 GAMING PRO CARBON AC ATX TR4 Motherboard (£339.99 @ CCL Computers) Memory: Corsair - Vengeance LPX 64GB (4 x 16GB) DDR4-3333 Memory (£549.99 @ Amazon UK) Storage: Samsung - 960 EVO 500GB M.2-2280 Solid State Drive (£204.00 @ Aria PC) Video Card: Asus - GeForce GTX 1080 Ti 11GB Founders Edition Video Card (£663.62 @ Amazon UK) Case: Corsair - Carbide 400C ATX Mid Tower Case (£72.00 @ Aria PC) Power Supply: Corsair - RMx 850W 80+ Gold Certified Fully-Modular ATX Power Supply (£115.98 @ Ebuyer) Operating System: Microsoft - Windows 10 Home OEM 64-bit (£82.20 @ Aria PC) Wireless Network Adapter: TP-Link - TL-WDN4800 PCI-Express x1 802.11a/b/g/n Wi-Fi Adapter (£26.98 @ PC World Business) Monitor: LG - 34UC79G-B 34.0" 2560x1080 144Hz Monitor (£479.97 @ Amazon UK) Keyboard: Logitech - K120 Wired Standard Keyboard (£15.13 @ More Computers) Total: £3581.82 Prices include shipping, taxes, and discounts when available Generated by PCPartPicker 2017-08-03 22:06 BST+0100
  16. I guess this is more directed at pipeline TDs, but I'm wondering how people do studio wide installs and updates (for new Houdini builds, but also for Maya service packs, environment file updates etc) on Windows. Previously we've done everything manually but this is obviously inefficient and more and more time consuming as the studio grows in size. Ive been looking into it and it seems SCCM and GPO are pretty common for this kind of thing as well as msiexec scripts - though it seems you only get an exe from sidefx so I guess I would have to convert that to msi? We use deadline for our render farm which is able to do 'maintenance jobs' which can execute a batch script once on each slave so that (with an msiexec script) could be an option. If anyone could mention their current solution or any advice on this that would be great. Cheers, Mike
  17. Automated remote install on multiple PCs

    Great, I'll try that out. Thanks very much for your help!
  18. Automated remote install on multiple PCs

    Hey, thanks for your reply. I have used bat files much before, is there any good documentation for installing Houdini or Maya using them?
  19. UI Dialog Help

    I imagine this is very simple but I find building ui's with python a bit tricky (compared, for example, to Maya which is very straight forward). I want to create a simple window (or dialog or ui) with several text fields, float fields, int fields etc. I have it working with hou.ui.readMultiInput, but you don't have much control in terms of layout/styling or what data types are allowed/expected. What are the best functions for this kind of thing?
  20. UI Dialog Help

    Thanks Craig, I did come across that library and it does look nice so I'll probably end up using that, just a shame there's no standard functions for this kind of thing..
  21. Houdini Pyro - Collision resize

    The gasresizefluiddynamic node resizes pretty much all the fields in the simulation, however if you have a collision volume that is moving through the sim you surely don't need that to be the same size as the density field, it just needs to be large enough to contain the collision object. Is there a way to set this up? I tried cracking open the node and removing collision and collisionvel from fields parameter in gasresizefield_smoke, I then created a separate gasresizefluiddynamic for just the collision fields. But for some reason my collision fields are still resizing to be the same size as the density field..
  22. Houdini Pyro - Collision resize

    They will until the gas resize node resizes them right? Then they will resize to fit whatever you have in the tracking field (e.g. Density). So I had hoped I could have a separate resize just for the collision and collisionvel which just tracked by the collision field that I'm sourcing, but it doesn't seem to work...
  23. Custom PC build advice

    Thanks Peter, thats really helpful. A lot of what you went for is what i'm looking at, so good to know i'm on the right lines!
  24. Custom PC build advice

    Ok thanks, also there are rumours that the geforce 20 series with Volta may be released this year (Q3), do you think its worth waiting for these to be released?
  25. Custom PC build advice

    Hey, thanks very much for your reply, really helpful! Ok, do you think 1080ti is the best option? (better than say a quadro p4000?)