i did this for a lucozade job where a dancer was emitting stuff based on his motion. I used a duplicate frame with a one frame offset to get a basic velocity and just set the weightmap value with that, using a rescale node and a scalar curve node to give a bit more control. A>
........................................................................... http://www.hackneyeffects.com/https://vimeo.com/user4174293http://www.linkedin.com/pub/andi-farhall/b/496/b21 http://www.flickr.com/photos/lord_hackney/ http://spylon.tumblr.com/ This email and any attachments to it may be confidential and are intended solely for the use of the individual to whom it is addressed. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Hackney Effects Ltd.If you are not the intended recipient of this email, you must neither take any action based upon its contents, nor copy or show it to anyone.Please contact the sender if you believe you have received this email in error.------------------------------------------------------------ From: grahame.ful...@autodesk.com To: softimage@listproc.autodesk.com Subject: RE: weightmap driven by velocity? Date: Tue, 22 Oct 2013 16:10:12 +0000 For something quick and dirty, then before the simulation node you can pop the last item out of the StrandPosition array and insert the current PointPosition into the first (zeroth) position of the array. The length of the strand will be proportional to the average velocity over the last n frames, where n is the size of the StrandPosition array. gray From: softimage-boun...@listproc.autodesk.com [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Chris Johnson Sent: Tuesday, October 22, 2013 11:33 AM To: softimage@listproc.autodesk.com Subject: Re: weightmap driven by velocity? Thanks for all your help everyone...much appreciated. Alok...way over my head and Jaff thanks for the visuals...I got it built then I had no idea what to do with it? Ha! So here's what I'm trying to do. I've attached an image as well as a link to the scene file if anyone should be so helpful? My creative director wants to see strands coming off an animated person based on velocity. So I showed him a test which is dead simple of strands coming off XSI man, with Mocap on him. The strands are being emitted from a weight map. My thinking was that the velocity of the geometry could drive the intensity of the weight map and there by emit strands when something is moving quickly...so in essence there would be short strands where the body is moving at a typical to slow rate but the hands and feet would be accentuated as they move fast. Then, to add to the complexity I want the same velocity, ideally to drive the life/length of the strand. If anyone can give me some further direction it would be greatly appreciated. ScreenGrab https://www.dropbox.com/s/z7007jvn4g9p2dd/strandsTest.jpg Scene Filehttps://www.dropbox.com/s/or7wluccec12knt/testForClient_velocityTest_10.scn On Mon, Oct 21, 2013 at 4:54 PM, Jeff McFall <jeff.mcf...@sas.com> wrote:I think this will work for both cases where you are using a deformed mesh (point position) or just the velocity of the geometry itself. I have both setup in this sample As mentioned earlier you may probably need to rescale or normalize some values jeff From: softimage-boun...@listproc.autodesk.com [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Chris Johnson Sent: Monday, October 21, 2013 4:05 PM To: softimage@listproc.autodesk.com Subject: Re: weightmap driven by velocity? so as there is no tutorial....and I 'm not that technical...how do you get a geometry's velocity?...The follow up question to that will be how do I drive that into a wieght map....sorry bit of a hack when it comes to ICE On Mon, Oct 21, 2013 at 3:45 PM, Eric Thivierge <ethivie...@hybride.com> wrote:Actually little tip, you can set the weight map min / max to other values to change the range of values aloud in it through ICE. On Monday, October 21, 2013 3:35:14 PM, Sandy Sutherland wrote:A Weightmap can hold greater than 1, so you just need to feed into a self.foo or something and see what your top level is, then add a weightmap that goes up to that level. Then just fire stright into the WM. Unless you want it to normalise to 1 as Alok says. S. On 2013/10/21 9:29 PM, Alok Gandhi wrote:Don't know of a tutorial but I guess you can take the magnitude of the velocity and plug it into weight values. Of course you will need to normalize to [0, 1] using a rescale. On 10/21/2013 3:23 PM, Chris Johnson wrote:Anyone know of a tutorial out there that shows how a weight maps intensity can be affected by velocity? Can you do that in ICE? -- ALOK GANDHI / directeur technique senior- senior technical directoralok.gan...@modusfx.com <mailto:alok.gan...@modusfx.com> T: *450 430-0010 x225 F: *450 430-0009 www.modusfx.com <http://www.modusfx.com> --------------------------------------------------------------------------------------------- MODUS FX 120 Rue Turgeon, Sainte-Therese (Quebec) CANADA J7E 3J1 Follow us onFacebook <http://www.facebook.com/ModusFX> & Twitter <https://twitter.com/Modusfx> **
