chazfest Posted January 2, 2012 Share Posted January 2, 2012 Hi all, Any ideas why I'm getting no render of my smoke sim? I've attached the project file for reference if anyone's kind enough to take a look? The sim cooks fine in the viewport, but just doesn't render out through Mantra. Not sure if it makes any difference at all, but the scene was sent from a Nuke project, where the camera was also tracked using the in built cameratracker. I only mention this as I built a smoke sim immediately prior to this project in a fresh Houdini project and everything rendered without a glitch. Hope someone could shed some light on this? Huge thanks in advance. CityScape Houdini2.hip Quote Link to comment Share on other sites More sharing options...
mawi Posted January 2, 2012 Share Posted January 2, 2012 Hi all, Any ideas why I'm getting no render of my smoke sim? I've attached the project file for reference if anyone's kind enough to take a look? The sim cooks fine in the viewport, but just doesn't render out through Mantra. Not sure if it makes any difference at all, but the scene was sent from a Nuke project, where the camera was also tracked using the in built cameratracker. I only mention this as I built a smoke sim immediately prior to this project in a fresh Houdini project and everything rendered without a glitch. Hope someone could shed some light on this? Huge thanks in advance. The subnet containing your camera is scaled x50. Often no good idea to work with scaled cameras. Quote Link to comment Share on other sites More sharing options...
DanBode Posted January 2, 2012 Share Posted January 2, 2012 (edited) To expand on that, it seems that the scaling of your camera is throwing of mantra's volume step size calculation. Greatly lowering this can help. I was able to get comparable results from your scaled camera, to an unscaled camera by doing doing an inverse of the scale on your camera to the volume step size and scaling the density by the same amount as you're scaling the camera. In your scene, divide the volume step size by 50 and multiply the density on your smoke shader by 50. Edited January 2, 2012 by DanBode Quote Link to comment Share on other sites More sharing options...
mawi Posted January 2, 2012 Share Posted January 2, 2012 (edited) I think this will be correct. 1. Create a copy of the camera. Kill the transformation and rotation. Then move it outside of the subnet. 2. Create a fetch node and pick the camera inside the subnet. Tick the "use parent transform of fetched object" 3. pipe the fetch into a blend node. make sure to unclick sx, sy, sz in the blend tab. and... 4. pipe that into the copy of your camera. Now you have killed the scaling but moved the camera to original cameras world-position and rotation. Edit. And render with your new camera. camFix.hip Edited January 2, 2012 by mawi Quote Link to comment Share on other sites More sharing options...
chazfest Posted January 2, 2012 Author Share Posted January 2, 2012 Thanks so much guys! Mawi, that's perfect! Can't wait to try it out when I get my new license. I've been experimenting on a station at work, but this station's moved elsewhere now I'm going to get me an Apprentice HD license seeing as it's so cheap! Do you know if I'll still be able to import FBX scenes into it? That's the only method I currently know to get Nuke scenes into Houdini. It all sounds perfectly logical when you explained it as above, but I'd never have thought of it!! Thanks again Mawi Quote Link to comment Share on other sites More sharing options...
chazfest Posted January 4, 2012 Author Share Posted January 4, 2012 Just a quick note to say that worked perfectly! Thanks Mawi Has anyone got any recommendations for learning resources for Houdini? I can only assume I'd need to look at the beginners stuff, I love messing around with fluids and smoke sims but just pick it up as I go along really. I'm a video editor and compositor mainly, so use FCP and Nuke on a daily basis, but Houdini really grabs me every time I use it and I'd love to really start getting my head around it. Y'know, get past the stage of pure experimentation and guess work Thanks again guys. great community. Quote Link to comment Share on other sites More sharing options...
altbighead Posted January 4, 2012 Share Posted January 4, 2012 Just a quick note to say that worked perfectly! Thanks Mawi Has anyone got any recommendations for learning resources for Houdini? I can only assume I'd need to look at the beginners stuff, I love messing around with fluids and smoke sims but just pick it up as I go along really. I'm a video editor and compositor mainly, so use FCP and Nuke on a daily basis, but Houdini really grabs me every time I use it and I'd love to really start getting my head around it. Y'know, get past the stage of pure experimentation and guess work Thanks again guys. great community. http://vimeo.com/user2030228 Quote Link to comment Share on other sites More sharing options...
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