Chris S. <chr### [at] bluelectrodecom> wrote in message
news:3988aceb@news.povray.org...
> For some reason, the 100% transparent alpha-channeled sections of my .png
> image map are showing the color specified in the background{} statement,
as
> shown in the image below, instead of the color behind it. [snip]

Try putting max_trace_level 50 (or higher) in the global_settings{} block of
your scene.

Attached are some pics which may help.  The first shows a scene without any
max_trace_level, the second with it set at fifty.  Spot the differenence.
The last two show the png image used, and it's mask/alpha channel.

The image was mapped onto a box using the following code:

#local alpha_thing=box {-0.5 0.5
  texture {pigment {image_map {png "robo_head" map_type 0 once}
translate -0.5}}
  scale <1,1,0.0001>
}

The scene was rendered using MegaPOV0.5a, if that makes a difference.

Hope this helps,
Alan.

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Attachments:
Download 'alpha_no_mtr.jpg' (35 KB) Download 'alpha_mtr_50.jpg' (35 KB) Download 'robohead.jpg' (9 KB) Download 'robohead_mask.jpg' (3 KB)

Preview of image 'alpha_no_mtr.jpg'

Preview of image 'alpha_mtr_50.jpg'

Preview of image 'robohead.jpg'

Preview of image 'robohead_mask.jpg'