Invisible texmap pattern

[Travis Cobbs]

This part

is now present at the Part Tracker, but the TEXMAP pattern is not visible from behind, when I use it in LDCad, on a transparent part.


Is it possible to combine a TEXMAP pattern with a BFC NOCLIP ?
If so, how should a correct file syntax look like?

First of all, please note that the same thing happens in LDView. In LDView, it's definitely due to a bug. (Unfortunately, it's a bug that would take a VERY long time to fix, and probably won't be fixed.) The bug in LDView is that LDView doesn't support TEXMAPs being applied to transparent surfaces, so the surface the texture is on is opaque. The reason that this relates to BFC is that in LDView, BFC is never applied to transparent surfaces. So if it weren't for this bug, the texture would be visible from the back side in LDView.

I'm not sure what happens in LDCad. It could be that LDCad applies BFC to transparent surfaces. If so, I would argue that that is a bug. It also could be that LDCad doesn't support TEXMAP on transparent surfaces. That would also be a bug.

The following might work, but isn't appropriate in an official file, since the disappearing texture is due to a renderer bug and not a part bug:

Code:

0 Dish  4 x  4 Inverted with White and Aqua Swirl Pattern
0 Name: 3960p0b.dat
0 Author: Philippe Hurbain [Philo]
0 !LDRAW_ORG Unofficial_Part
0 !LICENSE Redistributable under CCAL version 2.0 : see CAreadme.txt

0 BFC CERTIFY CW

0 !KEYWORDS Round, Elves

1 16 0 0 0 1 0 0 0 1 0 0 0 1 s\3960s01.dat
0 !TEXMAP START PLANAR -40 0 40 40 0 40 -40 0 -40 3960p0b.png
0 !: 1 16 0 0 0 1 0 0 0 1 0 0 0 1 s\3960s03.dat
0 !: 0 BFC INVERTNEXT
0 !: 1 16 0 0 0 1 0 0 0 1 0 0 0 1 s\3960s03.dat
0 !TEXMAP FALLBACK
1 15 0 0 0 1 0 0 0 1 0 0 0 1 s\3960p2b.dat
1 16 0 0 0 1 0 0 0 1 0 0 0 1 s\3960p2a.dat
0 !TEXMAP END

For reasons that I don't understand, the above doesn't work in LDView. I will be investigating that. What it's supposed to do is include a second copy of the textured geometry, and have that second copy face the opposite direction. It doesn't work, and I don't yet know why.