sand blasted glass

[prey1979]

Hello all i was wondering if anyone knows how to achieve the affect of say a plane of glass for example a table top or glazing partitions and have a pattern apear to be sand blasted on to one of the faces?
thanks
Ryan

[rodigus]

Try glossy refractions with a dent or small noise map in the specular slot. That could do it.

[prey1979]

hmm ok i will try that but say its one sheet of glass and i want a sand blasted design in the centre ofit how can i do that?

[egz]

use a blend material with a glossy glass material in one slot, a regular glass material in the other, and a bitmap to control placement.

[Da_elf]

why not use a mask in the glossy slot?

[Dusan_Pavlicek]

Because when you decide (during the tweaking process) to change glossiness values, it's much simpler to do that with the Blend material (changing only two float values) then to recreate the whole glossiness bitmap if you had a mask in the Glossiness slot

[egz]

egzactly

[Da_elf]

doesnt the blend material need a mask? which you would need to change?

[egz]

Why would you need to change that unless the shape of the frosted design iteself changes? You might want to play with the amount of glossiness though, and that is a lot faster with a blend material than it is with mapped glossiness.

[Da_elf]

works fine here though putting the mask in the glossyness slot. and all i have to change is the spinner next to the slot

[Dusan_Pavlicek]

But that changes only one of the glossiness values, doesn't it?
Of course, if you want one of the materials to be a perfect mirror (glossiness=1.0), then it is OK, but in case of a more complex situation the Blend material seems to be a more flexible solution. (Also if you for example want to change more params of the material than just simply glossiness...)

[Da_elf]

sure. if you want to change things like color of glass its usefull

[prey1979]

thank you all for the response and the discussion im going to try these methods out.. however i dont understand what was ment by using a bitmap to control placement does anyone mind elaborating on that technique?

[Dusan_Pavlicek]

It means to use bitmap as a mask to blend between the two materials (glossy and mirror-like)
[edit: so for example, you create a bitmap with white background and some black text written on it and you put it either in the Glossiness slot or in the Mask slot of the Blend material...]

[prey1979]

ah yes i figured that out hehe stupid question of me

but i still cant get the glass to look like its sand blasted or etched does anyone have any setting of a good sandblasted glass?