Render Vray problem for coffee material. Help me please.

[alexaustralia]

Hello,

 

This is my first post on this forum, I would try to be as much accurate as possible to explain my problem, because this one makes me crazy. (Sorry for my english, I will try to do my best)

 

I've modeled a cup of coffee. I've used the Compound objects to model the coffee inside the cup, and I use the cup itself in the compound object.

 

I've applied a coffee Vray material to my coffee object the same way as I would do for the water (diffuse color black, reflect color RGB to 232, check "Fresnel reflections", refract color white pure, IOR 1.33, Reflect on back side, and a dark brown Fog color for the coffee color.)

 

The problem is that during my render, there is no refraction at all ! I would like to be able to see the spoon throught the liquid.

 

When I launch the render, during the light cache pass, everything looks good, but, when the render is done, I lost my opacity, and the spoon isn't visible anymore.

 

Light cache

[ATTACH]46761[/ATTACH]

 

Render

[ATTACH]46762[/ATTACH]

 

can you help me please ? I don't understand where does the problem come from, should I change my render settings, or am I using the wrong material?

if you needs a screenshot from some settings, please ask me.

 

Can you help me to understand why it doesn't work and how to resolve it. Can you also explain me where are the settings I'll need to change because I don't know exactly where all the different elements in the vray are.

 

 

Ps : I've started to learn Vray few days ago and I'm, obviously, not an expert yet .

 

 

Thanks a lot for your help

 

Alex.

[Ismael]

Turn the Reflection off altogether until the Refraction problem is solved.

Go here and study the Vray material parameters, particularly the Fog...

http://www.spot3d.com/vray/help/150SP1/material_params.htm

Happy Studies!

[Corey Beaulieu]

I agree with Ismael. Reduce your factors and you can usually resolve the issue, but if you want help, could you post a screenshot of your coffee material?

[alexaustralia]

Thanks both of you for your fast answer. I try in few minutes, and if it's not working, I will post screenshot of my coffe material. Thanks again.

[alexaustralia]

Ok, I have set my Reflection off, try again, but it's still not working. I have print two screenshots of my coffee material, and a render with this settings. Again, thanks for your time.

 

[ATTACH]46766[/ATTACH]

[ATTACH]46765[/ATTACH]

[ATTACH]46764[/ATTACH]

[Corey Beaulieu]

my compputer is frozen and I'm waiting it out, so I can't test that material setup, but if I had to guess I'd say to place your Max Depth value back at 5 as is default. When this value gets above the reflection depth it starts to report a solid color. If they are equal it will be a true refraction.

 

Here is a good overview: http://www.spot3d.com/vray/help/200R1/examples_material.htm#refraction_depth

 

from the same source Ismael put up earlier.

[Corey Beaulieu]

So I'm unfrozen now and checking it out. I was wrong in my above. The higher max depth reports more solid only where and object doubles over itself.

 

I can't seem to recreate your issue except for in two instaces. One: by turning off GI altogether. I know this isn't it as you said you are at least using light cache, and Two: when using a dark brown fog color on an overly high multiplier of 1.0 and no Bias.

 

Try it again Using a dark brown Fog color with a multiplier of 0.03 and a bias of 2.75. I am getting this to work with and without reflection with everything else set the way your material is set.

 

Truthfully I'm not sure why this worked entirely, but it did. The only issue, however, that I cannot recreate is your purple transparent coffee in light cache and solid black/brown in final image. There still could be a greater issue at hand, but I'll have to leave that to someone else, I'm just not sure.

 

Good Luck.

[alexaustralia]

I have tried your settings, it's working with a dark red Fog color (good for red wine !, but with a dark brown/black for the coffee color, not at all).

 

I think, it's an other problem, because I have download a Coca Cola Vray .mat (it's perfect for my coffee material), and it's the same thing : during the light cache, it's work's fine, but when it's the last pass for the final image, all my refraction disapear !

 

Do you think the light, or my Vray settings may cause the problem ?

 

Vray coca cola material

[ATTACH]46784[/ATTACH]

 

lightcache with coca cola material ("nice" refraction)

[ATTACH]46783[/ATTACH]

 

final render (no more refraction)

[ATTACH]46782[/ATTACH]

 

Please, help me.

[cafric1]

I had a similar issue. I had no idea what was wrong with it, but I simply deleted it and remade it with that same settings (afaik) and it worked. It might be a bug.

[Corey Beaulieu]

Feel free to post a screen grab of your render settings. I just don't at all see how it could be the light. I thought material for sure, but maybe it's a settings thing. A camera problem would be doubtful, but who knows.

 

If you post your settings try to include the Vray, gi, and settings tab with as many rollout menus as you can.

[Ismael]

I bet is modeling:

http://vray.us/vray_tutorials/vray_rendering_surface_interfaces.shtml

http://www.aversis.be/tutorials/vray/vray_glass_liquid.htm

[alexaustralia]

Ok ... I found the problem .... please, don't kill me ! It was my cup material, there was an Ambiant Occlusion dirt map on it. I have never learn that refraction and dirt map was not advisable

 

I'm sorry to waste your time on that stupid mistake.

 

Thx again, Ismael and CoreyMBeaulieu. Have a nice day.