Can anyone pinpoint whats wrong with my dew on my beer?

[thethule]

Hi there, i am attempting to create a beer bottle with some dew on it. I know its been done to death, but i figured it would be good practise.
I cant quite seem to pinpoint whats wrong. I know its close, but not close enough. I am using a bump map rather than displacement for speed, though the logo is displacement map.
Here is what i have so far:



And here is what im after:



This is the bump map i am using (i scaled it down to post):




Thanks for looking


regards,

Marc

[schroeder]

Doens't look like you're getting specular highlights from the dew to me. Someone else here could probably better tell you how to do that.

[Dynedain]

your bump is also looking either a bit too sharp, or a bit too much

[flipside]

I think you are just putting a bump on the green glass material. The bumps are drops of water, so a completely different material. I would make a mask too and make a blend material (blend glass with water). And use displacement instead of bump.

wouter

[DaForce]

Mmm interesting bump map. How did you create it?

My initial though would be to give it a hit in photoshop to see if you can get some smoother bumps, cause at the moment it has very sharp colors so your not going to get a smooth bump.
It would be a matter of selecting, filling with white, then gaussian blur a few times with a lower pixel size each time. To get a nice smooth gradient type bump on this drops.
Now that might help you with your problem, but you material could be the culprit as well.

Whats your material setup for the glass?

[Syclone1]

Nice start but I also agree about the materials should be seperate and the glass and the water will have different IOR's also and probably different specular settings also.

-dave

[thethule]

Of course, that makes total sense. The dew is a different material to the glass, therefore a straight bump map wouldnt work. So obvious. DOH! I will do what you guys suggest, and post the results later this evening. Thanks!

Mmm interesting bump map. How did you create it?

I found a dew image on google images and modified it in photoshop, but you are right DaForce, it needs more work. As for my glass settings:





Thanks,

Marc

[siliconbauhaus]

nice start I'd call it condensation not dew

[jujubee]

Good start. Definitely play with lowering your glossiness levels by .5 increments on that material.

[Da_elf]

one of the things i notice is the flat white tops on your bump map. a water droplet wouldnt have a flat surface. your going to need to blur that to smooth that out

[flipside]

I did some test with water drops on a bottle.

If you use a blend material for your bottle (blen of glass and water material) and control the blend with a mask, rendering gets extremely slow. I remember something about this problem which was related to max and not vray. It would be better to make one material and control everything with mix maps in reflection/refraction/color etc...

So best and easiest way is to have the drops as seperate surfaces. This can be done by copying the bottle, and adding displacement to only the outer surface (delete inside) and use the water level function of vraydisplacement to clip the 'bottle regions' away. That way you can easily give materials to the drops and to the bottle seperately (and it's a bit more physically correct, altough not completely).

You should make a water drops map for the whole bottle instead of tiling it (altough in your case with these tiny drops this will not make a big difference).

The water drops map you use is wrong because they have highlights and stuff on it. You should have a real depth map which represents high and low areas of the drops.

I modified your map easily in photoshop:



Here a test render (note you see the drops on the back of the bottle because my liquid material is very transparant).



And a very short anim: (divx!!)
http://users.pandora.be/stor1/vray/bottle01_divx.avi

This also renders long but not as long as with a blend material. By adjusting the displacement you can tweak it to render a lot faster I guess.

Kind regards,

wouter

[Da_elf]

well. from what i can see there your bottle also has those flat water droplets which im not sure that possible in nature is it?

[flipside]

Yeah still a little bit, but that's easily fixed by adjusting the displacement map. This was just a quick test The white area in the map is still too big, altough this only happens on the big drops. I think you're confusing the reflections on the drops with flat areas too.

[thethule]

Good start. Definitely play with lowering your glossiness levels by .5 increments on that material

Jujubee, you mean have glossy refs on my glass? I tried that and found that it made it look like plastic as opposed to glass.


Flipside, thanks for that, thats is a very good idea, using a separate object layer for the condensation and using the water level. I did notice that using blend materials slows down the rendeing enormously. I assumed it was a Vray thing, not Max (sorry Vlado!)

I am at work at the moment, but i will try all the techniques suggested when i get home (after i see Star Wars) and post some results.

Thanks again



Marc

[thethule]

Just wanted to write quickly that i have been in bed with bad tonsilittis since last saturday, so i am not dropping what i was trying to do, just have not had the energy of chance to get to trying your suggestions.

Soon though, ill post an update when ready.


Thanks,

Marc