Transparency Map Ghosts

[SplineSoup]

I'm working with a small team on a short animation where a character walks through a room filled with obscure objects floating in large test tubes. Based on previous still image work, I immediately thought of using image maps to speed up the production process (since modeling dozens of obscure wispy objects would eat up a lot of time). What I ended up doing was creating two perpendicular planes and mapping them with front and side views of the same object. All looks reasonably well when both planes are about 45 degrees rotated from the camera view but when one of them rotates parallel to the camera direction it creates an obnoxious dark line in the middle of the object. See attached movie....and ignore the fact that the head parts don't line up!

 

My next idea would be to set up a material expression that causes the planes to gradually increase transparency as they approach a parallel angle to the camera and fade back into opacity as they rotate perpendicular again. I'm at a loss about how to do something like this, though, short of keyframing material transparency levels by hand. How can I set a material to change based on viewing angle? Is this possible without knowledge of scripting?

 

Bueno,

Chris

FloatingThing.mov

[Ganthofer]

Here is a test and the project file (vc14c) to look at.

 

Put your front and your side decals on the objects "front" and "side" .

 

I tried using one object with patches at 90 degrees, but couldn't get the constraint to work.

 

This version has 2 object Front and Side (rotated by 90). I added a bone (not attached to any CP's in the model) for each model. Dropped the models into a chor and constraned the 2 bones (one in each model) to aim at the Camera. then added an expression (in the chor) to the surface property Transparency for each of the 2 models.

 

This is on the Front Modle

If(Abs(..|..|Bones|Bone1.Transform.Rotate.Y)<45,0,If(Abs(..|..|Bones|Bone1.Transform.Rotate.Y)>135,0,100))

 

This is on the Side model

If(Abs(..|..|Bones|Bone1.Transform.Rotate.Y)<45,100,If(Abs(..|..|Bones|Bone1.Transform.Rotate.Y)>135,100,0))

 

If you have questions, I'll try and answer them.

Glenn

 

-New test and Prj with png ghost images

GhostTest01.zip

ghosttrans.mov

Edited February 3, 2008 by Ganthofer

[phatso]

Sounds like pretty simple keyframing. Betcha it would be faster than trying to set up something automatic.

[SplineSoup]

This is on the Front Modle

If(Abs(..|..|Bones|Bone1.Transform.Rotate.Y)135,0,100))

 

This is on the Side model

If(Abs(..|..|Bones|Bone1.Transform.Rotate.Y)135,100,0))

 

If you have questions, I'll try and answer them.

Glenn

 

Glenn, thank you for the expression sample. It's a little choppier than what I have in mind but I plan on studying your project file to deconstruct how you're getting this version to work. By the way, nice interpretation on the running/jamming/ghost/shadow/thing. With a bit of experimentation and exploration I stumbled across the ToonNation X-Ray shader, which does the exact *opposite* of what I'm trying to do, and was mildly consoled. What I'm trying to do doesn't seem possible with materials at this point unless I've missed something. I'm recalling working with gradients in another program and being able to link the gradient ramp to surface angle which lent itself well to things like soap bubbles and velvet. Keyframing it is...

 

Here's the next incarnation of the shadow guy with the transparency of two choreography layers keyframed in opposition. As one fades in, the other begins to fade out. This cured the distracting stripe that occurred when the planes turned into the camera. While it still looks a little funny in a full rotation, this is actually more than adequate to give the illusion of volume in a walkthrough scenario. I may even devise a 45 degree view to transition this rotation further, like those classy sprite-based FPS games of the 90's. They'll be floating, inert in tubes when all is finished.

 

Chris

FloatingThing_trans.mov

[Tai Shan]

Very cool! Want to see more as the work progresses.