• Bugs
• Use Alpha Channel for transparency

Issue

In ArchiCAD 8 and 9 when rendering with the internal engine the check box "Use Alpha Channel for transparency in rendering" does not in fact work.

Cause

This checkbox will allow you to use the Alpha Channel information of the opened background picture if it has any. White color of the Alpha Channel will make the background picture dominant, while black color of the Alpha Channel will make the photorendered image of ArchiCAD dominant over the background.
Note: If the background picture has no Alpha Channel and this checkbox is checked only the background picture will be seen!

Solution

Using a unique colour for the background may suit some images as it makes it easier to select that colour in Photoshop. Otherwise use a white background colour.

CategoryRendering, Alpha_Channel