View Full Version : 2-point polys and transparency

10-13-2011, 10:59 AM
I don't use 2-point polys very much but am trying to make some laser beam looking things. So I made 2 long 2-point polys out in a thin V shape for the beams and a third 3 point poly between them to simulate the laser light illuminating dust in the air.

Both surfaces have a Turbulence texture on the transparency channel to do the smokey look/break up the beams.

However on my 2-point beams, the texture doesn't show... the beams are completely solid lines. But it does show in reflections! Is this normal? Attached is a pic.. you'll see the broken up line reflected in the TV screen and on the floor (which has reflection blurring which is why it's so fat)

It's easy enough to just make a tiny extruded box to get around this instead of using 2-point polys, but I was more curious why it behaves this way.

10-13-2011, 03:10 PM
I think, but don't know for sure, that 1 point and 2 point polys are always rendered as 1 pixel (or whatever you set in Object Properties -> Edges -> Particle/Line thickness) points, or a line of 1 pixel points, and this is the case no matter what your output resolution. (if you double your output resolution, your lasers will still be 1 pixel wide). Effectively these objects are two-dimensional and have no volume, but you could try attaching a hypervoxel to it to make it laser-like.

Is your reflection blurry? It looks like the beam is just being spread out because the reflection is somewhat diffuse? (Although I'm not exactly sure how that works for a no volume 2d object as the reflectee).

I haven't used two-point polys, but I have used 1 point polys in a star generator and they seem to work this way. I haven't tried to texture them with anything more complex than a solid color with luminosity though.

10-13-2011, 04:07 PM
i;m thinking, maybe animate the opacity of the object instead...

10-13-2011, 11:23 PM
I did wind up just making a small extruded box instead which worked fine.

I just found it curious that the primary 2-point poly geometry (as it were) rendered solid, but the reflections of it rendered "correctly" showing the texture I had going in the transparency channel of the surface (the reflection you see in the sample I posted isn't segmented because of antialiasing or anything, it's how it should have looked.. if I increased the line thickness in the object properties, it gets heavier but otherwise looks the same)