Transparent Background Opaque Through Glass

alvordr

alvordr

0
Transparent Background Opaque Through Glass

Hey. I just made the camera have a transparent background for rendering purposes, which, of course, works great. However, when rendering the background through glass, it shows up as black. Other than the emission properties, there is no reason why this should be the case.

There is a cube primitive underneath the glass with a web screenshot as the texture. Towards the top you'll see the black I'm talking about. Where it looks black towards the top, it should simply be transparent.
 

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That is simply not possible yet - same with png/tiff+alphas against transparent background - think it´s going to be covered by the new material system.

Cheers
Frank
 
Good to know. Regardless, Cheetah is proving to be an invaluable tool in my designer toolkit. I played around with the Silo trial today a little and still think Cheetah is far better. The usability is way easier than Silo. I couldn't even find the render options in Silo to configure POVRay. LOL
 
That is simply not possible yet - same with png/tiff+alphas against transparent background
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The workaround:
  1. Set the camera to a flat (opaque) color background, and render twice using two different colors (e.g. BLACK and WHITE)
  2. take the resulting images into Photoshop and DIFFERENCE them. Now take the difference (copy merged)
  3. open one of the two files and switch to quick mask edit mode,
  4. paste the difference* into it,
  5. switch back out of mask edit. You'll either have the background or the image selected perfectly (can't remember), so invert if necessary and then
  6. convert selection to layer,
  7. and hide the original image.
You may want to remove black/white matte on the result (depending on which original you used) but you should have a PERFECTly masked selection, even working around specular reflections on glass.

Incidentally, the same workaround will work for motion graphics, but you'll need to render the animation twice, create a new animation based on the difference (should work pretty much the same as in Photoshop in FCP, Avid, Premiere, or After Effects), save that out, and then use it as a mask layer (not sure if FCP Express will support it). Worst case you can probably finagle it using QuickTime Pro.

* Difference compositing is an incredibly useful tool in Photoshop, more often for finding problems or defects in images or precisely matching pieces from two images than producing a final image. Difference creates an image that's black where two images are identical and white where they're completely different. Since you're rendering the same thing twice with two different backgrounds the ONLY differences will be in the background.

I played around with the Silo trial today a little and still think Cheetah is far better. The usability is way easier than Silo. I couldn't even find the render options in Silo to configure POVRay. LOL
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Silo isn't really designed for rendering, so I think the comparison is a bit unfair. Insofar as C3D's features overlap with Silo's, I'd suggest Silo is by-and-large the usability winner (e.g. edge boundaries conform to subdived surfaces -- that alone is a huge win). OTOH Silo has no concept of a modifier chain, so if you're extensively using C3D's modifier chain, Silo is utterly useless. Similarly Silo's materials are useless for anything beyond UV mapping.
 
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As far as usability, I started Cheetah fresh some 6 or so months ago. It took literally a day with no help to figure out how to model and texture a room with a bookshelf, a ceiling light, a rug, a lamp and more. I used Silo afterwards, knowing a lot more about modeling, texturing, lighting, etc., and in one day, I'm still wondering how to do much more than morph a box.

It's all relative, I guess, but for me...Cheetah wins hands-down.

As far as rendering, I understood that Silo doesn't render by itself, which is why I mentioned that I couldn't find the render options. All the help I could find to setup POVRay with it suggests there are render options, in which to setup POVRay as the rendering engine. I couldn't find "rendering options" anywhere.
 
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alvordr said:
As far as usability, I started Cheetah fresh some 6 or so months ago. It took literally a day with no help to figure out how to model and texture a room with a bookshelf, a ceiling light, a rug, a lamp and more. I used Silo afterwards, knowing a lot more about modeling, texturing, lighting, etc., and in one day, I'm still wondering how to do much more than morph a box.
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"morph a box" is what Silo does. It lets you morph a box into a Ferrari or Admiral Ackbar's head.

I'm not really trying to start (or win) an argument about C3D's usability vs. Silo 3D's, but this is like saying 'I learned to use a hammer and then I found this "Dremel" thing and it's a really terrible hammer, why I can't even find "hammer nails" in its manual, that's how bad it is.'

Now, if you don't need Silo's functionality or can't be bothered to learn it, then fine, but the fact it's hard or impossible to do stuff in Silo that it's easy to do in C3D is irrelevant. It's difficult or impossible to do a whole bunch of things in C3D that are easy or even trivial in Silo. Try extruding an edge in C3D.
 
podperson said:
"morph a box" is what Silo does. It lets you morph a box into a Ferrari or Admiral Ackbar's head.

I'm not really trying to start (or win) an argument about C3D's usability vs. Silo 3D's, but this is like saying 'I learned to use a hammer and then I found this "Dremel" thing and it's a really terrible hammer, why I can't even find "hammer nails" in its manual, that's how bad it is.'

Now, if you don't need Silo's functionality or can't be bothered to learn it, then fine, but the fact it's hard or impossible to do stuff in Silo that it's easy to do in C3D is irrelevant. It's difficult or impossible to do a whole bunch of things in C3D that are easy or even trivial in Silo. Try extruding an edge in C3D.
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We'll have to agree to disagree. Of course, some methods, such as extrusion may be more obvious in Silo, but I can make arguments for various methods in either direction. This does not negate the fact that getting anything relevant done in Silo for me has been more difficult. The process for extruding an edge in C3D can be pretty simple:

Select Edge
Press C
Move edge

I don't argue that Silo has merits in some of its capabilities. I'm only stating the user interface is way more difficult for me to grasp.

Referring to the picture attached, I can't tell you how exciting it has been to create such a fun and useless shape. I'm glad I tried Silo before buying it.
 

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frank beckmann said:
Try to "Cover" it then
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Neat! But *not* an advertisement for C3D's usability ;-)

OK for other examples: try beveling (oops sore subject). Try sculpting. Try retopologizing. Try editing the base mesh of a subdived surface without toggling the subdivision on and off constantly. Try explicitly working in a given coordinate system. Try snapping.

Referring to the picture attached, I can't tell you how exciting it has been to create such a fun and useless shape. I'm glad I tried Silo before buying it.
Click to expand...
It's not like C3D's "extrude" (et al) is any more intuitive than Silo's "slide" (et al).

Is having a "ball" appear at the origin of an operation better or worse than having the axis widget appear at the the (global) origin? I'd say better since at least you have some vague idea of what you're doing.*

I'm actually surprised you're having such a negative reaction to Silo since it's really very similar -- in both positive and negative ways -- to C3D in most respects where they overlap (perhaps it's "just similar enough that the differences are infuriating", like coding in JavaScript and PHP at the same time).

* I'll say something blasphemous here and suggest that Blender is more functional, more consistent, and more intuitive than C3D in this respect, since you can explicitly determine the frame of reference of any operation (view, surface, local, or global coordinate system). In C3D extrudes are in "surface normal" space (whether you like it or not), "cover" simply leaves you with new geometry to transform (generally in global coordinate space), and if you want to explicitly work in any other space, well good luck to you. (Silo has the same functionality as Blender w.r.t. coordinate systems, but it doesn't provide as nice and explicit a UI for it. Again ... blasphemy!)
 
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LOL, nice responses. I have to say that it's probably all moot, anyway. I can't get POV-Ray to perform the renders (it's how I'm not configuring it correctly, no doubt). That said, when I try to run POV-Ray by itself, it crashes consistently, so that's even more frustrating. For my part, I'll stick with Cheetah for now. If I buy anything from this point forward, I'll be saving a hefty buck for Modo.
 
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