Saving a Render with Alpha
(aka: There's a Croissant in my Brush!)
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Carrara
can save a rendering in several popular formats, including Targa which
is the default format of Project Dogwaffle. Furthermore, you can
arrange for the render to use the alpha channel to hold a mask of a 3D
rendered object against a transparent background. This makes it then
easy for use as brush images in custom brushes.
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Here's an example of
what to do and how to do it:
Start Carrara (in this example Carrara 5 Pro), with an empty scene.
Drag and drop the desired model from the model collection into the
empty scene
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A quick test render
will show that the background is plain black.
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Switch to the Render room.
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In the Rendering tab, set your desired quality parameters such as
Anti-Aliasing level.
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Move on to the Output tab
Set the desired image dimensions for your upcoming renderings.
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Let's first do this for a single image. Make sure it'll render the
Current frame, not the whole movie.
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Also set the file type to Targa to match Dogwaffle's favorite and
default format.
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There are some options available for Targa format output.
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Should probably choose
32 bit format if you want to save the apha channel with it.
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Then be sure also to check "Render Alpha Channel"
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You're ready to Render.
Click the [Render] button in the lower left corner.
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Wait until the rendering is completed. Then select the menu:
File > Save As...
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Make sure the output format is Targa. It should be defaulting to that
since we selected that as the output file format before rendering.
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If the Options
checkbox was checked in the prior dialog window, you will have one more
last chance to select the bit depth . Make sure it stays on 32-bit
depth so that the Alpha channel is not lost in saving.
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You may want to repeat this for a few more renderings, at different
angles or sizes of the croissant. Switch back to the 'Assemble ' room.
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use the Rotate tool
(keyboard shortcut 'r') and change the object's orientation.
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Here's a second
rendering:
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Repeat a few more
tims, at other angles. It all depends on whether you'll want to build
an animated brush and from how many frames.
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Here's we've got already 4 rendered images and a 5th being saved.
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Loading
the Image into Dogwaffle
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Switching over to PD
Pro, select
File > Open...
to open one of the Targa files saved from Carrara.
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If the alpha channel isn't showing, it doesn't mean necessarily that
it's not present. Be sure to use
Alpha > Alpha on/off
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Now you should see the animated marching ants outlines around the
rendered object. This is a hint that the alpha channel was properly
rendered by Carrara and shows the opacity mask based on the object vs.
transparent background.
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Using
the object as Brush
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From the Brush menu, pick up the selection into the custom brsh:
Brush
> Use selected as brush
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As son as the brush is created, be sure to store/manage it
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Now you can easily
paint with it, or just click a few times to stamp it down at various
locations.
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And that's it.
You're now ready to create many more new custom brushes based on a
rendering of 3D objects, with transparency masks in the alpha channel.
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