VRayDistanceTex with animated objects

[DNART]

Hi!
It would be veeeery nice to have an option that allows you to create a trail if you use the map with animated objects!!
That's my wish

[super gnu]

yes, ive often thought some kind of cache for the distance tex would be a very nice alternative to the various hacky methods to achieve the same, that we have now.

distance tex is amazing, and that would add another whole level of usefulness. tyre marks, footprints, dirt/damage and destruction sequences, wetmaps, it would be very powerful.


ideally it would allow a framerange to be specified, and also allow subframe sampling, and maybe a "time falloff" (useful for wetmaps) where the effect fades out over a given time.


im not sure if such a thing is straightforward to achieve however. id imagine it would almost certainly require some form of rendering out to an image sequence and reapplying using uv's.. (which is 75% of the hacky way we do it now) , since its a rendertime effect based on geometry distances..

unless it could cache the ray hits themselves and render as if the geometry from all previous frames was present.

[DNART]

Hi super gnu.
Thank you for your reply!
Yes! I have to make a roll painting a wall and it would be perfect to leave the trail where it passes ...
(do you have any alternatives to propose? )

[super gnu]

well the only simple way i know is to adjust your scene so the brush intersects the surface slightly, then render a flat view from behind the surface. this will give you a mask of the contact point.

then you have to use aftereffects or similar to comp together frame 1 + 2, then frames 1+2+3 etc etc..


if the brush is moving slow enough this will work. if its moving too fast, youll get gaps in the paint trail, so rendering out subframes becomes necessary.


you could possibly also force vray to do it using the same setup, an incredibly long motion blur, and some post work, but ive not tried this.

in your case you might also be able to use the "ghost trails" plugin for max, but im not sure if it even still exists.


you could also do it with pflow, have the brush tip emit particles, and i believe there is an operator that will texture a surface based on particle collision.. rendering now so cant check.



here is where somebody more VFX oriented will show you a much more elegant way.

[DNART]

yes, I did that way once, I've rendered the plane (wall) and composited in AE...
I will try ghost trail too!
Thank you super gnu!!