Jordan Walsh Posted January 8, 2013 Share Posted January 8, 2013 Coming from a FumeFX background where you can rotate grid freely I was just wondering what do people do when they want the grid rotated (say 45 deg in the Y) for a more efficient sim (eg, long thin line of fire on a 45 degree angle)? Surely the answer isn't to rotate your scene geo+ camera pre sim then rotate the results of your sim post sim is it? Quote Link to comment Share on other sites More sharing options...
ikarus Posted January 9, 2013 Share Posted January 9, 2013 It isn't much work to plug in a transform before and after your sim is it? Quote Link to comment Share on other sites More sharing options...
bloomendale Posted January 9, 2013 Share Posted January 9, 2013 (edited) Why not transform pyro/smoke sim as you do with fumefx grid? Attach Position data to pyro/smoke object (using Position DOP for example) and then write relative path to it in object. Edited January 9, 2013 by bloomendale Quote Link to comment Share on other sites More sharing options...
Solitude Posted January 9, 2013 Share Posted January 9, 2013 +1 for what Bloomendale suggested -- I only came across this a few months ago when I accidentally left the mouse over the position data path for too long. I thought it was more complex than that. It's not. That being said, I think it should be in there by default. Quote Link to comment Share on other sites More sharing options...
Jordan Walsh Posted January 9, 2013 Author Share Posted January 9, 2013 Cheers guys... that seems to work a treat, in typical Houdini style Quote Link to comment Share on other sites More sharing options...
Graybush Posted January 19, 2013 Share Posted January 19, 2013 Hahahaha Solitude just showed me this a few weeks ago when i was trying to figure it out. It should be in there by default. It ends up being one of the first things I do when I start a pyro sim if I need it or not. Quote Link to comment Share on other sites More sharing options...
MENOZ Posted January 20, 2013 Share Posted January 20, 2013 (edited) well, actually not everything is working always, I still prefer to transform object and transform back after the sim. Example file that shows incorrect sourcing of velocities. the "position" node is bypassed, try to activate it and see that the velocity is not computed correctly volumeOrientBUG.hip Edited January 20, 2013 by MENOZ Quote Link to comment Share on other sites More sharing options...
bloomendale Posted January 20, 2013 Share Posted January 20, 2013 well, actually not everything is working always, I still prefer to transform object and transform back. Example file that shows incorrect sourcing of velocities. Forgot to attach file? Quote Link to comment Share on other sites More sharing options...
Solitude Posted January 22, 2013 Share Posted January 22, 2013 Good to know! I didn't notice because I hadn't really had a reason to use it yet. I'll have to look for a workaround... Quote Link to comment Share on other sites More sharing options...
Jordan Walsh Posted January 22, 2013 Author Share Posted January 22, 2013 well, actually not everything is working always, I still prefer to transform object and transform back after the sim. Example file that shows incorrect sourcing of velocities. the "position" node is bypassed, try to activate it and see that the velocity is not computed correctly Good to know!! Has this been reported as a bug by any chance? Quote Link to comment Share on other sites More sharing options...
MENOZ Posted January 23, 2013 Share Posted January 23, 2013 yes, I reported it months ago, but I don't know if it's in progess of being solved, or if they give more priority to the bugs with more reports. Maybe if someone else will report it again it gets more interest from sidefx?? Quote Link to comment Share on other sites More sharing options...
Jordan Walsh Posted January 24, 2013 Author Share Posted January 24, 2013 yes, I reported it months ago, but I don't know if it's in progess of being solved, or if they give more priority to the bugs with more reports. Maybe if someone else will report it again it gets more interest from sidefx?? I reported it again.. They asked for an example file and I sent them the one you attached to this thread.. hope that's cool. Quote Link to comment Share on other sites More sharing options...
bloomendale Posted January 25, 2013 Share Posted January 25, 2013 (edited) I'm curious what is intended behavior of field with Position data provided. As said in help card transform is going after sampling. And it works so if you apply position data to one field. I attached simple example. Then it should just sample anything in world space (let's say box at origin) and then applies Position data: To get this behavior all you need is uncheck "SOP Output is in simulation space" in all Sop solvers in Fluid Source DOP because we don't need double transforms from sop solvers and Position data of the containers. But if it should transform container without touching its data then it have to do it before sampling or resample all data. So i think 1st behavior is what was planned. 3ak_fields_Position_data_PROBLEM.hipnc Edited January 25, 2013 by bloomendale Quote Link to comment Share on other sites More sharing options...
jkunz07 Posted May 13, 2016 Share Posted May 13, 2016 I know that this thread is much too old, but here is a file which fixes the issue. I have modified /obj/dopnet1/sourcevolume1/source_tempvel so that the vel volume is sourced properly even in a rotated domain. volumeOrientBUG_fix.hip 8 1 Quote Link to comment Share on other sites More sharing options...
MaxGyver Posted September 26, 2016 Share Posted September 26, 2016 Was facing the exact same issue. Your solution works like a charm, even with Pyro Clusters. Thanks a lot jkunz07 Quote Link to comment Share on other sites More sharing options...
Chats Posted May 19, 2021 Share Posted May 19, 2021 Heya I know this is an old topic, but I'm having real trouble in sourcing velocity in world space and then it having very strange behaviour in the Pyro sim when transforming the bounds with a position DOP. It seems to stamp the velocity into the sim in the correct world space (ie after the bounds has been rotated by the position DOP), but then it evolves in the sim as though it were traveling in the direction of the bounds before the position DOP rotation is applied. It's hard to explain and I can't upload an example right now, but I wanted to check if anyone has found a modern solution to this (Houdini 17.5) with the newer volume sourcing nodes? Cheers! Quote Link to comment Share on other sites More sharing options...
Chats Posted May 19, 2021 Share Posted May 19, 2021 Ok so I just realized that on the DOP import fields SOP, when "transform by position data" is on, it doesn't transform the vector of the vel field correctly, the workaround is to turn that off, then convert to VDB, make sure it's transform type is set to "velocity/displacement", and then manually transform the frids back into the space 1 Quote Link to comment Share on other sites More sharing options...
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