A set of Light Streaks

[Theresa]

Hi all could really do with some help...

I found a video on youtube that shows beautiful light trails:

http://www.youtube.com/watch?v=uyhKhCFklVI&NR=1&feature=fvwp

Im trying to do this in houdini however when i instance lights to particles the rendering takes ages... The video tutorial for maya seems to be extremely fast am i going the correct way about this using particles ? How could this be setup to be fast

Thanks

Light_Streaks.hipnc

[Macha]

If you use PBR rendering, try emission settings. (export a parameter called ce in your shader, or use the emission settings in the mantra surface material. Or, try a geometry light. Or, best perhaps, do it in post.)

Edited April 29, 2011 by Macha

[Theresa]

If you use PBR rendering, try emission settings.

So use the constant colour instead of rendering lights ?

Guessing rendering X amount of lights will kill the system ? as i want the effect to be realistic.

Thanks

Edited April 29, 2011 by Theresa

[Stalkerx777]

Here is an example. Very simple setup.In this case i've used geometry light.

simpleTrail.hipnc

[Theresa]

Here is an example. Very simple setup.In this case i've used geometry light.

simpleTrail.hipnc

Hi,

Thanks for the reply i got something similar to this earlier using the constant shader and applied it to your scene. Im suprised that the geolight renders quicker than using a simple constant shader.. Although im still trying to get a more realistic ghosting fade as in the reference image from before.

I had also considered reducing the shutter speed on the camera to capture a point light moving across as this would render faster hopefully.

simpleTrail_Constant.hipnc

[Theresa]

Hi,

Been Searching for a solution for quite some time now and still not much luck.. All im looking to achieve is something similar to the reference image above does anyone know a way of achieving this look ?

Does anyone know how to set a couple of ramps parameters for particles ?

A ramp to control the Alpha fading the particles at one end of the trail.

A ramp to change the colour over the length of the trail or skinned geometry.

Thank You

Edited May 1, 2011 by Theresa

[Stalkerx777]

I think the main reason,why this effect using particles in maya, thats because there's no way (without scripting or API) to make this effect in maya. But in houdini, you probably don't need particles(maybe,only for generating points), you can do it completely procedurally in SOPs.

I think all that you need is to watch this Peter's tutorials.

[Theresa]

I think the main reason,why this effect using particles in maya, thats because there's no way (without scripting or API) to make this effect in maya. But in houdini, you probably don't need particles(maybe,only for generating points), you can do it completely procedurally in SOPs.

I think all that you need is to watch this Peter's tutorials.

Hi,

Yea i have went over Peter Quint's tutorial and still not getting the right asthetic, Peter clae's tool basically does the same thing and thats what im using atm however, again still not quite there..

Essentially wanting to get the most out of houdini but am also using nuke which should help.

Thank You

[anim]

...

A ramp to control the Alpha fading the particles at one end of the trail.

A ramp to change the colour over the length of the trail or skinned geometry.

...

i have just answered suspiciously similar question at sidefx forum

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=22108

[kubabuk]

Woulnd't be easier to output some additional planes such as P N Pz and perhaps a Velocity Attiribute to fake Motion Blur and tweak the image in COPs?

[Theresa]

Woulnd't be easier to output some additional planes such as P N Pz and perhaps a Velocity Attiribute to fake Motion Blur and tweak the image in COPs?

Possibly im not sure how to do that though, i take it Pz is a depth pass ? N normal ? P ?