My first post...
I'm trying to get images for an animation in a tutorial. The frames will consist of a moving LED beam.
I've got it working, but I'd like the gradient used for the beam to be more representative of the the actual light dispersion.
The density of the gradient should fade from left to right, AND
the density of the gradient should fade as a function of the "off angle". Brightest on the sensor pole immediately adjacent to the pole, and fading off as the angle get larger. For example, 50% intensity at +-7 degrees.
That's what the actual radiation pattern of the LED is. Decreasing with the square of the distance, and decaying to 1/2 intensity at +-7 degrees. Having the graphic reflect something like the actual dispersion of light will help make some of the points of the tutorial more intuitive.
I think I should be able to get what I want with a gradient/mesh/transparency and or mesh fill. Maybe combining multiple objects somehow. But, I've played with all those tools and can't get what I want.
Ignoring the need to also fade from left to right, I can get this using the fountain fill with linear gradient. But, even this subset of the task isn't what I want. The gradient is vertical, versus radial around the emitter point:
I tried elliptical gradient, but the gradient starts from the center of the object. Maybe I could somehow combine and object with an elliptical gradient with its center over the emitter point source. But, I couldn't figure out to do that. I kept loosing the fill all together when I did virtual segment delete after combining the curves
I see a tutorial on how to do what I want in PhotoShop, so I'm about ready to give up and try that. I'm not that skilled in CD, but much better in CD than PhotoShop, So I'd like to stick with CD since this is just a small piece of the graphics I need to do for the animation.
Any help would be greatly appreciated!
This is close enough to what I need.
I first created a beam clone and used the interactive fill tool with elliptical fill to get the left to right gradient. Then I made a copy of the same beam and enlarged it slightly. Here are the two beams before I removed their outlines and chose
After removing the outlines of both shapes, I used the blend tool to get the top image. From there, I can convert to a bitmap and add blur or maybe other effects.
II think I can play with the difference in color between the two cones and their relative size to get something a little close to the actual emitter's radiation pattern (50% intensity roll-off at 7 degrees off axis).
I was hoping I could blend N different cones to get very close to the actual off-axis intensity roll-off, but it seems you can't blend more than two objects, or use an object group that's already been blended and blend again with another object. Please let me know if I'm wrong about that.
Regardless, what I have is very close to what I need. I'm spending so much time on getting it as good as possible, since it will be repeated hundreds of times in animation frames. So, I'll wait for any additional suggestions before I do that (tedious) work.
Thanks for the help!
Thought I'd post what I'm going with, lacking any other suggestions.
The optics on the emitters "focus" the beam to +/-7%. But, it's not like the intensity is zero once your off axis more than 7 degrees. That's just where the intensity is 50%. That's part of the point I need to make.
Anyway, the image doesn't reflect the actual off-axis roll off, but it's good enough for illustration purposes. It would be "nice" if the outside edge wasn't a line at all, but just faded all the way to white, but I don't know how to do that.
"I was hoping I could blend N different cones to get very close to the actual off-axis intensity roll-off"
Actually, you CAN do this.
The "trick" for me was to create the objects with the same left to right gradient. Then, I change the start gradient color to progressively lighter colors for the wider angle cones.
Starting at the center, I blended the the most acute angle clone to the next wider one. Then blended that "blend group" to the next wider cone, etc.
So, you can get the change in intensity versus off-axis as close as you are willing to bother--just more objects to blend.