ryee@sandstorm.Berkeley.EDU (Raymond Yee) (06/11/91)
Hi everyone, I'm looking for some advice about how to draw supercoiled DNA on an IRIS. On the scale that I am interested in, the coils should look like lines, or at the most, very thin rope connected in a closed loop. I've tried drawing DNA as lines in 3-D using depth-cueing and mapping the range of colours from (32,0,0) to (255,0,0) in RGB. I've also tried to bracket the near and far planes as tightly around the object as possible. However, I have found the results to be disappointing -- there just is not enough "depth-cueing" to easily resolve which part of the coil is in the front and which is in the back. (Before I go on, I should mention one thing. These DNA coils have many twists in them -- a bit like spaghetti -- so the challenge in displaying the DNA is getting very good depth cues in one way or another.) My questions are the following: 1) Should I stick with depth-cueing or should I try to draw the DNA as long, thin connected cylinders? Will the surfaces and lighting help depth perception a lot? If the cylinders are too thin, then will there be display problems? 2) If I stick with depth-cueing, should I try different colours? 3) On a different note, I also have questions about writing an interface to allow rotations and translations of the coil. I'm planning to use the 'virtual trackball' interface included in 4Dgifts. Have others used it? Does anyone care to share better ways to do the same thing? Thanks a lot, Raymond Yee (ryee@ocf.berkeley.edu)