exterior WIP

[highpoly]

By the way that caustics room teapot thing was mad crazy..how did you even think of doing that?

I am seeing what you are saying..thanks for helping me with this. the only thing my tests are showing though is that having refractive GI caustics on or off seems to dictates whether other lights (in this case environment) affect the materials behind the refractive one. It seems that 'affect shadow' is having no effect at all and that refractive GI caustics is what controls it, at least in your pool scene....that tells me that skylight is creating GI caustics that are affecting the area behind the material. skylight is certainly not included in the direct lights caustic soluition.

http://www.geocities.com/highpoly/BL...Iandaffect.jpg

is this right? by the way, great example and test scene

[highpoly]

ok..last test. I added an omni in there and made sure it wasnt included
in the caustic solution. i tried it both with affect on and off and it was exactly same.

i wonder if when you enable vray photon caustics, the affect shadow becomes nullified? or could it be not having an effect since we are not using the light from the max light to light the scene (diffuse and spec off).

can it be that photon caustics and refractive GI caustics are both having an effect? i guess so since turning them off made the surface behind the refractive material darker. this is making my head hurt. i need a GF.

[DaForce]

lol well you see... i fell pretty hard on my head that day and it just popped in.. but seriously.. not really sure.. just came to me one day as a cool idea.

If you have a room, with a window and a pane of glass, a direct light shining thru the window and a bright red environment color. The changing affect shadows or refractive caustics the following is witnessed:
1. Affect shadow ON allows the direct light to pass thru the glass
2. Affect shadows OFF stops the direct light from passing thru the glass
3. Refractive GI caustics ON allows the red environment to pass thru the glass
4. Refractive GI caustics OFF stop the red environment from passing thru the glass
They appear fairly independant of each other ( I thought they used to be locked to an extent)

Let me post the info from the helpfiles

GI caustics represent light that has gone through one diffuse, and one or several specular reflections (or refractions). GI caustics can can be generated by skylight, or self-illuminated objects, for example. However, caustics caused by direct lights cannot be simulated in this way. You must use the separate Caustics section to control direct light caustics. Note that GI caustics are usually hard to sample and may introduce noise in the GI solution.

Refractive GI caustics - this allows indirect lighting to pass through transparent objects (glass etc). Note that this is not the same as Caustics, which represent direct light going through transparent objects. You need refractive GI caustics to get skylight through windows, for example.

Reflective GI caustics - this allows indirect light to be reflected from specular objects (mirrors etc). Note that this is not the same as Caustics, which represent direct light going through specular surfaces. This is off by default, becase reflective GI caustics usually contribute little to the final illumination, while often they produce undesired sublte noise.

Affect shadows - this will cause the material to cast transparent shadows, depending on the refraction color and the fog color. This only works with V-Ray shadows and lights.

Hope that helps.. I may have muddeled things up a little earlier

[highpoly]

its getting clearer i think..

in your red environment example, was the direct light a vray light or max light? the last part of the help notes throws me a bit, since i thought that affect shadow was a way to get light to pass through clear materials with MAX lights, in fact the only way, but the help notes say Vray lights only. Do you know what I mean?

i thought affect shadows and refractive GI caustics were linked to, as in if you turn on affect shadows, vray disables GI caustics (as in wouter's tut below)
<www.aversis.be/extra_tutorials/vray_basic_material_settings_02.htm>

It makes sense in the pool scene that turning off refract GI caustics would make the pool darker (not allowing enviroment light to pass through)the water, but why turning affect shad on/off had no bearing at all i still dont know..

[DaForce]

I tried both direct and vraylight.. the results were identical. I think that part of the help file isnt all that clear.

Yeah well thats what I had kinda of thought. But certainly in my test scene, they were pretty independant of each other. I was only looking at the LC calc tho, but thats accurate enough.

Yeah I cant really say why affect shadows does nothing in that scene as it did in my test scene.
I will do a little testing.. got some ideas up my sleave.

[highpoly]

well, interestingly enough...just turning off photon caustics in the scene in vray caustics rollout, and the affect shadow works again. turning it on or off enables/disables GI caustics again. so in this scene the max light is now doing nothing. that must mean that when photon caustics are involved, affect shadow becomes disabled, i think...maybe...

i wonder if vlado could confirm/deny this...

[highpoly]

http://www.geocities.com/highpoly/BL...fectshadow.jpg

OK, I am really really sure I got...i think..no really! check out the test pic above. it seems ...

If photon caustics are OFF, GI caustics ON, and use MAX light only
------------------------------------------------------------------------------
-affect shadow ON is only way to get light to fake its way through ref material.


If photon caustics are OFF, GI caustics ON, and use VRAY light only
---------------------------------------------------------------------------------
-having affect shadow OFF will rely just on the GI caustics of the vray light. light will pass through, even though affect is OFF.

- having affect shadow ON will turn off GI caustics and light will also pass through and usually brighter it seems, but not accurate.


If photon caustics are ON, GI caustics ON, and use both MAX AND VRAY lights (as in the pool scene)
--------------------------------------------------------------------------------
-having affect shadow on or off has no effect. only enabling/disabling GI
caustics has an effect.

what do you think?
I think I have worn this topic out, eh? but at least i get it now....

[DaForce]

lol well I guess you knew what was up my sleve.. lol
Yeah those were the test I was going to do.

I think your post sums it up pretty well

[highpoly]

thanks ! (whew)... glad its over....
now i can sleep again...lol

thanks for your help and for that great test scene..

[DaForce]

hehehe enjoy the rest.
I woke up last night in a cold sweat screaming CAUSTICS!!!!

No problem, good to see you found it so usefull

[bernhard]

Fakie Caustic Gradient ?

Hello friends !

I've tried to make the caustic fake solution, but I have toubles with the gradient map.

Dont' know why, but I can't get a nice cut between the black and the white area. In my case, I would like to have the dark side from the pool (the shadow side) completly filled with my blue color from my gradient. But for some reason I don't understand, I get the blue color just a little bit in the corner.

How can I change that ?

Here is my image:


Here is my little scene file:
http://www.bernhardrieder.com/ask/Fake_Caustic.rar

thank you for every little help,
bernhard

[highpoly]

try using a falloff map set to 'shadow / light'...should do the trick

[bernhard]

hmmm...

well, thank you. I've tried it now with falloff, and yes, it works with the light, but not with my map. I used blue and black for the colors.

But what I would like to get:
In the shadow, you shouldn't see the texture.



I don't know why it didn't work with the gradient, it should.
Hmm, and maybe there is a solution with falloff too.

thank you so much for every little help,
bernhard

[highpoly]

yes, thats right..now you want to use a falloff map with the texture too so with 'light/shadow' so that places in light get the texture, places in shadow dont...make sense?

[DaForce]

In the max file you shared, simply move the 2 middle point in the gradient ramp further to the right.