how to animate points moving along their normals

Forums Houdini Indie and Apprentice how to animate points moving along their normals

5286 8 2


oat: Member; 479 posts; Joined: Dec. 2009; Offline

Feb. 20, 2013 3:44 a.m.

As shown below, I have a group of points with their normal/velocity and speed of movement (vel) attributes embedded.

may I ask how to animate the points moving along their normals/vectors in their respective speeds (defined by the “vel” attrib) in a looping manner, i.e. a point moves from its original position along its normal in a given speed to a distance as defined by its vector and speed, and start over again …

Thanks!

Attachments:
pt_animation.rar (68.2 KB)
1.JPG (96.7 KB)
2.JPG (53.1 KB)


zdimaria: Member; 390 posts; Joined: Jan. 2012; Offline

Feb. 20, 2013 6:22 a.m.

you can just add the normal multiplied by the velocity to the position. this will move them along the normal. i am not sure what you mean by the looping though. where do you want them to stop before they start looping?


zdimaria: Member; 390 posts; Joined: Jan. 2012; Offline

Feb. 20, 2013 6:23 a.m.

another way is to use the displace along normal vop and take the length of the vel as the displacement amount.


oat: Member; 479 posts; Joined: Dec. 2009; Offline

Feb. 20, 2013 11:22 a.m.

thanks!

I added particle node, but the points only show up one after another.

What should I do to make all the points move at the same time?

thanks again!


zdimaria: Member; 390 posts; Joined: Jan. 2012; Offline

Feb. 20, 2013 1:30 p.m.

theres a number of ways of doing this. this is the least number of nodes to do it that i can think of. i still dont understand what you mean by looping though

Attachments:
pts animation.hipnc (58.9 KB)


oat: Member; 479 posts; Joined: Dec. 2009; Offline

Feb. 20, 2013 10:27 p.m.

Thanks!

I also did some test as shown below:
particles emitting continuously from their origins in certain interval travel for a while along its normal for certain distance, and then disappear … This is the “looping” effect I was talking about which “fakes” the effect of a continuous flow of a group of particles

the only artifact (unwanted side effect) is that the animation seems to “twitch” a bit every one or two seconds …

Any advise on how to get a smooth and non-twitching effect?

Thanks in advance!

Attachments:
pts animation7.hipnc (59.2 KB)
pts.gif (128.0 KB)


old_school: Staff; 2540 posts; Joined: July 2005; Offline

Feb. 21, 2013 7:56 a.m.

My first thought is to create and populate volumes (vel.x, vel.y and vel.z per convention in Houdini) by the points with their velocities then advect the points wit the vel volumes.

Should be fast and without glitches.

There's at least one school like the old school!


oat: Member; 479 posts; Joined: Dec. 2009; Offline

Feb. 21, 2013 9:11 a.m.

Dear Master Jeff, thanks! But can you share a bit more on this approach using velocity volume?

Thanks in advance!


zdimaria: Member; 390 posts; Joined: Jan. 2012; Offline

Feb. 21, 2013 10:19 a.m.

this is (i believe) what he means.

Attachments:
foroat.hipnc (117.2 KB)

Quick Links

                    
                        Search links
                        Show recent posts
                        Show unanswered posts