display issue: burning through

Sometimes borders of transparent parts in png textures 'burn' through all faces and show the background behind. This issue is quite old and has been described by Matthias. I already mentioned a possible workaround, but I thought it should be posted here so that the Sketchup can maybe solve it finally.

1. It occurs sometimes in Sketchup as well as in Google Earth, there seems not to be any rule.

2. It has been assumed that pngs should not contain any semitransparent parts, only opaque or fully transparent parts. This is

not always true, because when a zoomed view is rendered, pngs are sampled with something like a bilinear filter which always causes semitransparency between a fully transparent and an opaque pixel.

3. Another tip was applying the png texture on front face and backface. This seems to help for the white-backside problem but not for this issue.

I spent many hours for modeling the European Parliament and got a quite ugly result that I could never ever publish in the 3d-

warehouse.

See this image: http://aerilius.ae.ohost.de/burningthrough1.jpg [dead link]

See here for the difference between burning-through and not:

http://aerilius.ae.ohost.de/burningthrough2.jpg [dead link]

http://aerilius.ae.ohost.de/burningthrough3.jpg [dead link]

I found out (by chance!) that I can solve it by putting all not transparent faces in one group. This way, there is no png face on the

same level in model hierarchy with any other face. PNGs seem only to burn through faces that are on the same level in model hierarchy, they do not burn through groups or components.

This post shall be a workaround for other modelers and a hint for the Sketchup Team where to search for the bug. If it is not possible to solve the bug, I could imagine that PNG faces and opaque faces can be put in different 'groups' inside Google Earth before display rendering.

Hi Olaf, thanks for this info. Little but extremely useful tips and workarounds are always welcome! I'll try to remember this any time I (or anyone in the need of help) encounter the issue.

Gai...