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Change an objects alpha.
show user profile  Dredwerkz
Because all 3DS has o say about "Alpha Channel" or Object alpha is this: -
I find I need to ask you guys, how do I change an objects alpha? Having done it before and forgetting where it is I'm getting very frustrated.

Alpha is a type of data, found in 32-bit bitmap files, that assigns transparency to the pixels in the image.

A 24-bit truecolor file contains three channels of color information: red, green, and blue, or RGB. Each channel has a particular intensity or value at each pixel. The intensity of each channel determines the color of the pixel in the image.

By adding a fourth, alpha channel, the file can specify the transparency, or opacity, of each of the pixels. An alpha value of 0 is transparent, an alpha value of 255 is opaque, and values in between are semi-transparent. Transparency is important for compositing operations, such as those in Video Post, where several images are blended together in layers.

An alpha channel is particularly useful for the partly transparent pixels around the aliased edge of an object in a rendered image. These pixels are used for compositing. An image such as the one shown above can be composited smoothly onto a different background if an alpha channel is produced and saved with the image.

Each channel of a truecolor bitmap file is defined by 8 bits, providing 256 levels of intensity. Thus, an RGB file is 24-bit with 256 levels each of red, green, and blue. An RGBA file (red, green, blue, alpha) is 32-bit, with the extra 8 bits of alpha providing 256 levels of transparency.

3ds Max creates the alpha channel automatically when you render. Any background pixels in the rendered image are fully transparent, and the alpha channel also accounts for any other transparency that you create via materials, etc. You can see this in the rendered frame window by clicking the Display Alpha Channel button on the toolbar: In the resulting display, black pixels are fully transparent, white pixels are opaque, and gray pixels show degrees of transparency. To return to the regular display, click Display Alpha Channel again.

To output a rendered image with alpha, save in an alpha-compatible format such as TIFF or Targa. With Targa, the default settings include saving alpha; with TIFF, be sure to turn on the Store Alpha Channel check box.

read 656 times
1/13/2009 1:46:36 PM (last edit: 1/13/2009 1:46:36 PM)
show user profile  mrgrotey
Thanks for the lesson, but what do you want to know? how to get transparency into a texture? how to get the alpha channel from a render? what?

read 655 times
1/13/2009 1:52:03 PM (last edit: 1/13/2009 1:52:03 PM)
show user profile  Kajico
do you mean the objects transparency? that's the transparency slot and slider in the material, or you can add a black and white alpha channel for mask out areas.

(\/) (°,,,°) (\/) Woop woop woop!

read 649 times
1/13/2009 1:55:48 PM (last edit: 1/13/2009 1:55:48 PM)
show user profile  Dredwerkz
lol, no, the second and onwards paragraphs are all I could get hold of in the help files, just saying how useless they are when all I want to find is a dialogue box.

Object alpha can be adjusted, so upon rendering it doesn't always have to be 1. I just can't remember where the damn setting is, could you tell me please?
read 647 times
1/13/2009 1:57:26 PM (last edit: 1/13/2009 1:57:26 PM)
show user profile  Sypher-5
You modify the objects material,.... which one would find using the material editor,.....
Signature Pending Redesign

read 638 times
1/13/2009 2:03:21 PM (last edit: 1/13/2009 2:03:21 PM)
show user profile  Kajico
Max calls them different things. You can modify the Opacity slider in the material (don't know why i said transparency earlier), or right click on the object and go to properties and modify the visibility.

(\/) (°,,,°) (\/) Woop woop woop!

read 636 times
1/13/2009 2:03:49 PM (last edit: 1/13/2009 2:03:49 PM)
show user profile  mrgrotey
Am I the only one completely confused here? Object alpha? You want to make the object less opaque?

[edit] the visibility track (and the visibility spinner in the object properties) are not compatible with mental ray, you need to use the material transparency instead

read 635 times
1/13/2009 2:04:05 PM (last edit: 1/13/2009 2:07:08 PM)
show user profile  Dredwerkz
Well opacity worked, but I swear there's a separate alpha setting so I don't have to render two images, one for the object the second for the alpha.

mrgrotey I want to render an image with a single object, the image in the RGB channels to be 100% opacity, but in the alpha channel I want the object to be 0.1 alpha. I swear there's a setting to do this, so I don't have to render the same thing twice to get different RGB channels from the alpha.
read 627 times
1/13/2009 2:08:06 PM (last edit: 1/13/2009 2:10:50 PM)
show user profile  Kajico
you don't have to render two images if you save it out as a tiff or a png or any other format that supports alpha channels.

(\/) (°,,,°) (\/) Woop woop woop!

read 624 times
1/13/2009 2:11:40 PM (last edit: 1/13/2009 2:11:40 PM)
show user profile  Dredwerkz
I know how to save alpha, what I mean is the object RGB opacity I want at 100%, but the alpha opacity at 10% or 0.1, I don't see it under object properties, is there anywhere else I can set an objects properties other than by right clicking then object properties.
read 621 times
1/13/2009 2:16:45 PM (last edit: 1/13/2009 2:16:45 PM)
show user profile  Kajico
why on earth would you want that? the opacity controls the alpha channel that's why the RGB is transparent because the alpha channel is telling it to be transparent.

(\/) (°,,,°) (\/) Woop woop woop!

read 618 times
1/13/2009 2:21:47 PM (last edit: 1/13/2009 2:21:47 PM)
show user profile  del3d
Never seen it, but sure sounds like a useful setting. Hope you find it.
read 616 times
1/13/2009 2:23:59 PM (last edit: 1/13/2009 2:23:59 PM)
show user profile  Jollabollathan


read 602 times
1/13/2009 3:44:18 PM (last edit: 1/13/2009 3:44:18 PM)
show user profile  Sypher-5
Render elements, "alpha" perhaps ?
Signature Pending Redesign

read 598 times
1/13/2009 3:45:20 PM (last edit: 1/13/2009 3:45:20 PM)
show user profile  horizon
I'd like one cheeseburger without cheese please.

read 573 times
1/13/2009 8:36:33 PM (last edit: 1/13/2009 8:37:04 PM)
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