compositing materials

[SgWRX]

hello. i'm drawing a blank. i have a small concession stand building with green metal siding, a cutout for a clear metal rolling door, a frame around that door, modeled seams, and a clear metal shelf.

 

i'd like to composite a logo the side of the building overlaying it like you might vinyl-wrap a car.

 

the building has a multi-sub object material on it with arch&design sub materials. i've created a 4th material (arch&design) and use a bitmap in the diffuse slot and a bitmap for the cut-out.

 

how do i overlay that logo without disrupting the sub-materials? is it even possible?

 

in the attached image, i photoshoped in a white outline and faded white area where i'd like the cutout material with the logo to go. you can see it overlaps the metal roll-up door and yellow frame and the metal shelf. so those are all assigned their own material id (1 thru 3).

 

i'm wondering if the only way to do it is to render the building to texture, then apply that as a base map in the "composite" with the logo over the top?

[John Dollus]

looks like the concession stand from my high school football field.

 

put the logo as part of your green siding material but turn uv tiling off and assign it a UV mapping channel of 3 (or whatever you haven't used yet). Next, apply that UVW map to your object, set to planar and match the size to your logo bitmap and change the channel ID to match your logo bitmap ID in the material editor.

 

I'm not at my system right now but pretty sure those are the steps. I'll check in a bit and post screencaps to clarify if needed

[Zdravko Barisic]

^

...and if the logo has some transparency, make the transparency color same as basic color of the metal, just pick up the RGB value of diffuse slot, and paste it in Photoshop.

Good luck!

 

PS - Sometimes, I do this kind of logo, by simply making of spline>extrude about 0.01cm with logo shape and matching it to wall.

In this case it could be done by shape marge, as you have those thin metal lines of metal sheet wall.

[SgWRX]

thanks. i do see what you're talking about. but i think that's still going to get me just the logo on the green part and not across the metal rollup door... but ah... i should should just do them both as separate objects (although i could do 1 object with different maps and id's) with the same uvw map and two different materials, the logo being part of both. i guess if they did it in real life, they wouldn't wrap the yellow frame or the metal counter (shelf) anyway.

 

i think i was looking at this the very hard way. typical

[Zdravko Barisic]

...some ideas, if you are not familiar with UVW channels, etc...just cut the part of the wall, with logo, place the proper UVW planar maping logo, and thats it. Very beginer way, but it works. Just use the same colors/mat, as on the rest of the metal sheets.

[Tommy L]

Use a blend material with the logo silhouete as the mask. Map the silhouette as a planar UVW on its own UVW id channel. No work in post required...

[SgWRX]

i got it. i did use the blend material, a&d logo in the first spot, then a&d green color in the second spot with a black and white mask as the blend mask. i then created another blend material same as the first only this time instead of the green color background, i switched it to the clear metal. but the same logo a&d material (color and mask) were in this one. then it was just simply selecting the roll up metal door and the side of the building (both at once) and adding on the uvw map.

 

a little off subject - i freaked out because at some point yesterday i must have checked the "re-use final gather" by mistake and was getting all sorts of blown out whites and weird colors. i thought it had to do with the layered materials and using "blend" or "composite". that's when i ended up reading some interesting things about non-physicality of "composite" (not sure if it's corrected now? that read was from 2010).

[SgWRX]

oh, it sounds like you can use multiple blends, nested. i'll have to try that.

 

and for some reason i couldn't quite get things going by using the same PNG file for the color logo and mask as part of the color logo was a white background. so that ended up being transparent.

 

i changed from a single PNG to two JPG's - one black & white mask and the other color with a black background. selected the logo in photoshop, contracted the selection by 1 pixel to get rid of the weird edges and i was all good.

 

 

EDIT: I should add that i looked at using the composite and mentalray material to shader so i could drop the green metal a&d material into one layer of the composite and the logo a&d material into another layer. that's when i started seeing all those funky colors because i had the re-use FG accidently checked. but that led to a search where it seems i found composite is not energy conserving like mr materials. i think i even got a render error "invalid color using black instead", but that may have been from FG re-use. anyway, there was a good thread after all that i've found where a guy was making a metal spray can with several layers of logos and text on it. not sure if it's OK to post links to other forums if not please remove, but here's that other thread: http://forums.cgsociety.org/showthread.php?f=6&t=874583&page=1&pp=15

Edited September 10, 2014 by SgWRX

[SgWRX]

Something else to add. Attached is a picture of a blend of two blend materials. the goal was, to be able to move the two words around via their uvw map gimzos. on the plane they are close together. on the cylinder they are further apart.

 

i originally had a "composite" with TWO layers, one with the shiny word and one with the smooth word. but to my surprise, i was able to turn off the smooth map (thus delete it and it's not in my material screen grab)!

 

i'm not sure exactly what's going on there? but it seems i need at least one bitmap in the composite which is wired into the mask.

 

so my question is: is this "right" to do it this way?

 

the rust map is channel 1, the smooth is 4 and the shiny is 3 (i guess that could have been 1, 2, 3 but somehow ended up with 1, 3, 4)

 

and thanks for everyone's input!!

[Tommy L]

You can nest blends. The composite material is not very good. Its inefficient at render time and can yield physically inaccurate results. In VRya the VRayBlend material lets you stack blends which is nice. The blend nesting is really the same thing but just a little tougher to keep a mental track of, especially with the editor in compact mode.

[SgWRX]

ok. so really i don't even need that composite node anyway since there's only one map (a mask) in it anyway. so i just removed the composite and all seems to still render OK with the ability to move it around with the uvw gizmo. thanks.