blobs of lights behind transparent glass

[nomeradona_cg]

i dont seem to understnad these lights behind the transparent glass. affect aplha and affect shadows on ( transparent material) caustic off.

[dalomar_cg]

Re: blobs of lights behind transparent glass

This was discussed in another thread. It came down to caustics of sun, so disable GI Reflective Caustics (top of the indirect illumination tab) or mess with the sun photons.

Here's the other thread. http://www.asgvis.com/index.php?opti...0&topic=2091.0

[nomeradona_cg]

Re: blobs of lights behind transparent glass

dalomar,

ok i uncheck the refract caustic actually, the refelctive caustic was uncheck. so its ok now.

i thick texturing is my biggest problem now. i dont really know how to lessen the obvious repetitive mapping of material. any guideline that you can share in making water material?

nomer

[dalomar_cg]

Re: blobs of lights behind transparent glass

Reflective GI caustics are unchecked by default...Refractive are enabled by default...

As for repetitive textures there is really only one true solution. That is to make maps that are big enough to cover the whole face and only repeat once or twice or even not at all. Having maps like that also allows you to go into photoshop and add some variations in different places. This is the optimal solution, but not everyone has the time to make maps for every face on their model. What you may try is some thing slightly in between that...in photoshop make a canvas that is double the size of your texture. Then place you map in each of the 4 corners, but mirrored, so that it looks like it was "unfolded". This will do two things. First it will make it "seamless" if it is not already. And second it will make the map bigger so that it repeats less. At this point you can do a bit of photoshop work to make things look like it wasn't mirrored exactly, but thats up to you. Also the offset tool is extremely useful for making sure that textures stay seamless.

Oh and I forgot water. I would say use our procedurals, but it think there was a bug where they couldn't be mapped very well (in Rhino though). Any way here's what I do. In photoshop I make a seamless noise texture and in order to do this it is very simple. First make a canvas that is square and some thing that is x^2...ie 2,4,8,16,32,64,128,256,512... you see what I mean (this is important to make the texture seamless). Then make sure that your canvas is filled with something (anything, but nothing will not allow this to work) and that your color palate has the colors black and white. Now go to filter>render>render clouds. This will make a seamless noise texture that you can use for water...if you don't like that pattern, just render clouds again and you've got a noise texture. Use that as a bump map on your standard water material and you should be good to go.

[nomeradona_cg]

Re: blobs of lights behind transparent glass

dalomar,

ok, i got it. i have tried this filter forge software to create my own maps ( automatic seamless tiling too and can create huge resolutions)unfortunatelly all the maps i did were small. as you know to save mb.
but now i'm craving for more realism to my models. thanks for giving the guidelines on this.

as for the water. i think i got it loud and clear. thanks.

[dalomar_cg]

Re: blobs of lights behind transparent glass

now i'm craving for more realism to my models.

Glad to hear you say more realism from your models. Having a highly detailed model is highly needed in order to make truly photorealistic renders. After a great model all thats left is materials and lighting, and depending on your scene that may be anywhere from a piece of cake to quite a task. However a low detailed model will only get you so far.

[Jorbu]

Re: blobs of lights behind transparent glass

In my tests, those bright spots were caused by the glas material not letting the sun through the material. Once I adjusted my transparency settings on my glass material those spots went away and the sun was coming through the glass.

You can see in this rendering the sun is not entering the space.

[dalomar_cg]

Re: blobs of lights behind transparent glass

It has nothing to do with the material (other than it being refractive), but has to do with the Sun itself. The issue comes down to Caustics and the way the sun emits photons. Because of the way vray relates to units, and also because of how units are handled in sketchup, the sun is basically emitting photons that are very large (hence the great big blobs of light). The reason your thinking that the sun was not coming through the glass was because of the large space between each of those photons. The simple solution is to simply tell vray to not worry about these calculations (disabling refractive GI Caustics), and assuming that you have Affect Shadows checked in your material settings then you should notice no difference. The better, and more involved, solution is to decrease the radius that the sun emits photons from (which spreads the total number of photons over a smaller area), or increase the number of subdivisions that the sun uses to calculate its caustics (this will in turn lead to longer rendertimes). Ultimately, since most users rely on Affect Shadows to "fake" the caustic effect, disabling GI caustics is the simplest and most efficient way of dealing with the issue.