Bump and distortions in glass across whole building...

[AcesHigh]

I once tried Artlantis at a friend. It had some kind of procedural glass shader which created deformations in glass similar to what we find in real life buildings... you know, when you look at some skyscraper full of glass, the glass panels are NOT completely flat.

I want to know how to reproduce that in VRAY. I guess that adding a bitmap bump to the windows will make that THEY ALL HAVE THE SAME bump, which would be quite realistic.

So, what I really want to know is how to spread a big bumpmap bitmap, or a procedural (perlin?) bump across multiple glass objects, so you wont have a pattern of reflection distortion along the hundreds of glass panels in the building.

Thank you!

[AcesHigh]

Re: Bump and distortions in glass across whole building...

this is the descriptionof the Artlantis Fresnel Glazing Shader

"Fresnel Glazing Shader
This very special shader perfectly
imitates large glass surfaces. You can set
independent color to transparency,
reflections, and define the shininess of
the material.
This shader can detect the windowpanes
and the distortion of the reflected image
individually in each pane.
You can also set the distance for the
reflected elements. It can be infinite, so
the limit is = 0.
"

[JHuman]

Re: Bump and distortions in glass across whole building...

Add a bump to the glass material. Using noise, you will just have to experiment with the size, I usually put around 20 to 40. Hope this helps.

[Jackson_cg]

Re: Bump and distortions in glass across whole building...

Just apply a solid black diffuse bitmap to your glass material, set the transparency, then edit the texture position in SU so the diffuse map fits the boundaries of a window pane and then apply a bump map. That way the same bump pattern will apply to each pane of glass, as if the distortion is relative to the frame holding the edges. For even more realism (i.e. bump relative to pane sizes plus a bit of random bump thrown in) just use a blend for the bump map.

[AcesHigh]

Re: Bump and distortions in glass across whole building...

Just apply a solid black diffuse bitmap to your glass material, set the transparency, then edit the texture position in SU so the diffuse map fits the boundaries of a window pane and then apply a bump map. That way the same bump pattern will apply to each pane of glass, as if the distortion is relative to the frame holding the edges.

sincerely, I did not understand whats the difference to the normal method (just using a normal glass with reflection and bump

For even more realism (i.e. bump relative to pane sizes plus a bit of random bump thrown in) just use a blend for the bump map.

how do I use blend on the bump to get random bump across the window panes (so far, all windows have the same bump, no matter how large or small it is... of course, thats unrealistic)

[Jackson_cg]

Re: Bump and distortions in glass across whole building...

Hopefully pictures will speak a thousand words!
Note that the reflection on the left glass panes is relative to each pane rather than globally across all of them like the ones on the right.
For varied bump combined with relative bump try blending two bumps maps with differing Mapping Types- "Explicit Map Channel" for one and "Object XYZ" for the other might do the trick.

[AcesHigh]

Re: Bump and distortions in glass across whole building...

many thanks. Will try that.

[AcesHigh]

Re: Bump and distortions in glass across whole building...

Thom, I was playing with blending noise, not as bumpmaps, but as diffuse (so I could see what really was happening).

anyway, I could not change the noise from panel to panel... each panel got the same noise texture, no matter how much I blended them, if I set some at planar and other on Explicit Map, etc

[Jackson_cg]

Re: Bump and distortions in glass across whole building...

Who is Thom? LOL

I've not tried blending bump maps in this way yet and unfortunately have way too many deadlines to mess around with them just now, but I'll post back here when I get a chance to play.

Jackson

[AcesHigh]

Re: Bump and distortions in glass across whole building...

where is the ashamed or red face smiley?

sorry Jackson... dont know why I thought it was Thomthom who was helping me here... maybe I had multiple tabs of the forum open...

anyway, I tried using the blending of the noise maps in the diffuse layer (easier to see than a bump layer!)

its really easy to set up a scene and add the blended noise maps (worth setting amplitude to 10, so its easier to see the noise). The difficult and time consuming part is to ACHIEVE the result I want

[AcesHigh]

Re: Bump and distortions in glass across whole building...

found these two threads dealing with the same issue on VRAY 3DMAX...

but I failed miserably at reproducing the effects at VRAY Sketchup
http://area.autodesk.com/index.php/f...wthread/17289/
http://3dsmaxrendering.blogspot.com/...bout-bump.html