Travis Cobbs Wrote:A number of years ago, Joshua and I collaborated on LDView's support for his proposed OBI LDraw extension. However, to the best of my knowledge, it was never proposed to the standards committee, and LDView disables support for it by default. If you want to use it, you need to set LDView's OBI hidden setting to TRUE (either by -OBI=1 on the command line, or via the registry; see LDView's help file for general information about setting settings). And in order to actually see any OBI rendering, you of course need OBI-supporting parts and primitives (which Joshua created for his personal use, but as far as I know haven't been published anywhere).
I'd give you more details, but the while the OBI syntax was designed (by Joshua) to be as simple as possible, it still isn't trivial, and I don't remember it off-hand. I could in theory reverse engineer it by looking at LDView's source code, but it would take a lot of effort, and I'd probably miss something anyway.
OBI was originally designed and built in Foundry, a part-editing application built by a non-ALE friend (who also worked on the design of TEXMAP) [side note: Foundry was also instrumental in working with the LDD format and was part of the tool chain that got us the last shipments of LDD parts through LU]. I started to try to port OBI support to LDView myself, but the graphics cache was unfamiliar enough to me that I enlisted Travis's help. Travis helped us to add some nice features to OBI (features that, when implemented in TEXMAP caused some consternation from other LCAD implementers, if memory serves).
OBI is really quite simple. The most basic syntax is:
0 !OBI NEXT OBI_BLACK
which will color the next non-comment, non-blank LDRAW line (the entire file, if the next line is a type-1) in color "OBI_BLACK" when OBI is turned on in LDView. (OBI_BLACK would be a color name from LDCONFIG.LDR)
There are also
0 !OBI START OBI_BLACK
and
0 !OBI END
for wrapping a series of lines to be colored
There exists other support for setting named flags and only colored conditionally based on how they're set, but that's pretty advanced usage, mainly for primitives that are meant to be used in a general way (sometimes you need it black, sometimes you need the primitive without the black support).
We weren't sure there would be wide-spread enough interest in the syntax, plus I had an ex-committee member recommend against certification, so we never really pursued it.