View Full Version : making it rain?

12-07-2004, 08:44 PM
i am trying to find a technique for adding rain water rippling off an object, not rainfall itself but the little ribbons of rain that stream down, pool into drops on a surface, this sort of thing.

anyone know of good resources for this sort of fx?

thanks all.

12-07-2004, 08:54 PM
Not sure if this is what you want, not seen it myself, http://www.3dtrainingonline.com/lightwavefxseries.htm


12-08-2004, 02:13 PM
thanks for the tip, it looks pretty close to what i am looking for.


let's see if any freebies exist... 25$ is a lot of money for me to blow on a tutorial.

12-08-2004, 05:54 PM
Try this site http://www.rustboy.com/rustweb.htm (goto makeing of) and hit number (3) not shure if you can intergrate it using lightwave. Also goto movies and number 16. This just shows that you don't need a highend software to do great stuff. good luck :D

12-08-2004, 06:38 PM
this is more like what i am after, the running down, dripping stuff.

hmm, interesting.
it appears it is just bump map work...

looks like i have to bone up on surfacing.

thanks a lot for the tip :D

12-09-2004, 06:04 AM
I'm glade I could help and if you figure it out and if it doesn't take too long think about a tutoral I think it would be a nice piece. :)

12-09-2004, 10:44 AM
i think i have most of it, i am replicating it in fusion first for mapping.
if i can get it i'll definitely do a tutorial.

12-09-2004, 06:18 PM
well it is one thing to have my image map but another to map it!

anyone have any ideas on that?

been trying a few things and not quite getting anything that looks like water yet.


(i am a compositor, not a surfacing genius, so no laughing allowed)

12-10-2004, 06:20 AM
UV mapping presumably?

12-10-2004, 06:14 PM
this is a still image from a looping, seamless tiled avi i made in fusion, following the tip leading me to the rustboy page. it seems to be a fairly simple solution.

i want to use it as a map on an object, so it looks like trickling, wet glistening rain running down a surface.
there is another one with just drops appearing, but same difference.

problem is, i do not know how i would actually go about the mapping.
it has to be more than just a bump map, i know that much :P

ok, so now it's all out there!
anyone have any ideas?

12-11-2004, 09:08 AM
mhmm, I don't know how far advanced you are, but wet surfaces have a lower diffuse value, a higher specular/reflection value, and perhaps some tweaking in the glossiness.....

could you be more specific, whats your problem ? maybe I can help

12-11-2004, 11:04 AM
advice and help is what i need :)
i haven't done surfacing in several years, and even then it was simple image maps, not anything fancy.

my best guess is that on top of the colour channel, i add another channel that would be similar to a glass surface, but like you said, high specular and glossy.
but bump too, these rain ripples have to stick out a touch.
anyway, that is my guess, not really knowing.
i'd appreciate pointers on the mapping though.

12-11-2004, 05:23 PM
Well if you're going to use it as a bump, also add it as a texture UNDER your colour texture, and set it to Texture Displacement in the blending mode drop down. This will 'cause your colour texture to 'refract' where the bumps are. Also add it in the specular and reflection channels to give that glint where the drops are.

12-14-2004, 04:43 PM
hey dodgy,
well your advice has definitely helped, however i am not getting the wet-glint like effect out of it.
i have that on the surface, but not on the actual water drops, which is what i need.
so, it just looks like the surface has this creepy disease of some kind, instead of looking wet and rainy.
(yes, i know the rain is flowing the wrong way on the wings, it is just a basic test at this point)
can you give more info on this perhaps? what did i do wrong?


12-14-2004, 05:11 PM
Looking at your texture, it should be shinier where the drops AREN'T because it's white there. You'll have to toggle Invert Layer in the texture to get it shiny in the drop areas :)

I guess your bump is set to -something?

12-15-2004, 03:58 PM
well i am now trying pfx with hypewrvoxels as an alternative method.

i have done a number of tests and get the results i want to.
i added the emitter & gravity to my scene and made my model a collision object, but this is where things go wrong--

once i try to change the 'type' setting to 'object' from the default 'sphere' setting, lw hangs and crashes.
this repeats every time i reopen my scene and try it again.

anyone know what might cause this?

12-16-2004, 01:54 AM
Man, what a lousy paint job on the plane ;) It looks like wet paint, but not like rain. You should use your bump map in the specular channel too and make a high specular for the drops and a low for the plane.
Regarding hyperwocxzels, you can double the plane model and add more polygones to it. Than delete the polys and use merge points to reduce the points, and manually delete some. Next you can apply HV with a water texture to it and you have rain drops. Not sure how to do the running drops.

12-16-2004, 04:28 AM
yeah I was thinking added the avi to the spercular map but I think it would have to be reversed (negative) so the rain drops are white. Good luck, Ive been trying to do a street scene with rain n particles - got it to look good falling but once it hits the ground it either looks like hail or sticks around looking silly so I think I'm gonna try the image map route

12-17-2004, 01:28 PM
well dodgy's advice has come through, i have great looking results, and it's just mapping.
i was playing with the pfx technique but it seemed problematic to me. was having a difficult time getting it to look like actual rain and not falling blobs.
anyway, mapping worked for me, thanks Dodgy!

12-18-2004, 07:01 AM
there is an old thread on CG talk leading to this site......
It's just what you're after.Run a search over at CGtalk for
WIP: Very Old Boot and CG Rain fx.

12-18-2004, 12:14 PM
thanks for the tip.
this fellow certainly got some fine results, however i was unable to find his postings for any insight into his technique.