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Ty Catt
04-04-2011, 01:22 PM
I know it was tossed around several years back (before nodes and v9), but has anyone come up with a good method for creating reflective tape / roadlines in LW?

I thought I had it bagged and I don't and now I am beginning to lose it. I'm guessing the light node and it's direction will drive it. I know glow was a seperate area in the Basic Editor and I am struggling to find the equivalent in the Node editor. I am thinking luminosity alone won't cut it.

I am not too keen on nodes, although I try to be. Right when I think I get nodes, I realize how far behind I am and I have to try harder to re-wire my standard Surface Editor hemisphere of the brain.

Thanks y'all.

jrandom
04-05-2011, 02:58 PM
I can try to help out with nodes if you can list specifically which areas are tripping you up. (I find nodes stupendously intuitive and absolutely hate the layer system -- with our two oppositely-wired brains there is nothing we can't do!)

As for reflective tape, I'm not sure exactly what you're trying to achieve, but if you can describe the effect to me I can do my best to help out.

Ty Catt
04-06-2011, 12:11 PM
Thanks for the reply, J.

THe trickiest things with nodes for me is this- it seems like everyone has the node input list memorized except me! I guess I should say that without knowing every single node possibility in that list, I just get overwhelmed. When LW 9.0 was released, t seems like the whole LW community understood what the hell a "scalar" was except for me. It felt like I missed some huge email explaining what the whole nodal tree was about!

I should say I don't use LW everyday and as a result am always playing catch-up. My job requires me to master about 10 programs, and LW usually falls to the bottom because I use it the least.

Not trying to whine, just being honest with myself. I have some learning to do.

That's why 95% of the time, I just resort to the good ol' Basic Surface Editor.

Here's what I am trying to do:

I have to animate the driver's perspective of a car driving around an inclined winding road whose headlights can't pick out some construction equipment until it rounds a flat (no incline) bend in the road.

I see there is a light nodal input (with direction as a sub-input), so I assumed my car headlights (as an nodal input) could to drive an objects surface. The other tricky thing is what simulates that reflective look- luminosity probably can't cut it alone, and I know that glow was an attribute that used to only be turned on or off, and (not that I can see) in the nodal input list.

Does that scenario make sense?

Sorry about the rant.:)

Thanks again!

Tyler

jrandom
04-06-2011, 12:30 PM
The trickiest things with nodes for me is this- it seems like everyone has the node input list memorized except me! I guess I should say that without knowing every single node possibility in that list, I just get overwhelmed. When LW 9.0 was released, it seems like the whole LW community understood what the hell a "scalar" was except for me. It felt like I missed some huge email explaining what the whole nodal tree was about!

I can completely relate to this. I'm just a part-time hobbyist and only know how to use a tiiiiiny subset of Lightwave. As a programmer, though, I already knew what things like "scalar" meant. :)

I scoured the documentation when I first got Lightwave 9.6, and while it is woefully incomplete, I was able to glean the basics of node input/output types and have a very good grasp on that now. If there are any that still confuse you, let me know and I'll type up a rundown on them. Not to toot my own horn, but I'm not too shabby at explaining things.



I have to animate the driver's perspective of a car driving around an inclined winding road whose headlights can't pick out some construction equipment until it rounds a flat (no incline) bend in the road.

I see there is a light nodal input (with direction as a sub-input), so I assumed my car headlights (as an nodal input) could to drive an objects surface. The other tricky thing is what simulates that reflective look- luminosity probably can't cut it alone, and I know that glow was an attribute that used to only be turned on or off, and (not that I can see) in the nodal input list.

Does that scenario make sense?

I'm still a bit lost... you want a surface to be invisible until lights are pointed at it? Wouldn't the objects be hidden by the initial incline and whatever the road is winding around? Is it reflective tape that is suddenly supposed to go through a high increase in reflectivity/brightness when the camera is close to them?

I still can't quite figure out what effect you're trying to achieve. Color me confused. :)

Ty Catt
04-07-2011, 08:15 AM
J.,

Thanks again for your reply.

Sorry about the confusing scenario. In it's simplest form, I need a surface which glows brighter only when struck by a particular light source (all the incline stuff is a detail about the case itself and really not pertinent to my problem).

So if you were driving along a dark road, your headlights would normally illuminate an upcoming object in the road. But if the object had a stripe of reflective tape, the tape would illuminate /glow sooner and stand out further down the road than just the object's standard surfaces.

I need to replicate that glowing surface attribute of a piece of relective tape on a normally surfaced object.

Is that better?

Thanks again!

jrandom
04-07-2011, 11:43 AM
Hm... in the real world this happens because the reflective tape reflects nearly 100% of the light that hits it, and reflects that light back in the direction the light came from more strongly that from an observer at an angle from the light source.

You could maybe take a Light Node, multiply it's brightness by a scalar (use trial and error to find the right value) and use that to drive the diffuse brightness and specular highlight strength of the tape (probably > 100% of the light that hits it). That would make it stand out against the other surfaces in the scene lit by that same light.

This doesn't fix the "at an angle to a distant observer" property of reflective tape, but if the camera is at the car driver's position and facing the same direction as the light, the above technique should theoretically work.

dwburman
04-07-2011, 11:48 AM
Here's a thread in which I show how to simulate the look you're looking for. If you keep reading the thread, you will find a node setup from Weepul that is more accurate.

http://www.newtek.com/forums/showthread.php?t=78393&highlight=road+sign

jrandom
04-07-2011, 12:00 PM
Cool!

Looks like I was halfway there, just didn't think of the now-it-seems-incredibly-obvious angle of incidence node.

Ty Catt
04-07-2011, 01:36 PM
Ahhh... now I see.

I don't know what I would do without kind folks like yourselves always helping me out.:)

Looks like I need to brush up on nodes, and this looks like a perfect scene to do it with. I can't wait to start.

Thanks again!

dwburman
04-11-2011, 11:50 PM
Basically, I started with the idea of over-driving the diffuse channel since diffuse determines how much light a surface reflects. You can do some freaky stuff with negative diffuse values too.