Lighting Question

[wfcentral]

I am having a conversation with a co-worker about the properties of light on cylinders. Can someone please help clear this up? I have posted an image that I whipped up in Xara X to illustrate the two views. I know that the tops of the cylinders are not shaded correctly...I'm more interested in the sides.

The question is. If light is hitting a cylinder at a 45 degree angle, will the cylinder be evenly shaded top to bottom like the cylinder on the left or will it have a diagonal shade like the cylinder on the right??

Thanks,
Robert

[Klaus Nordby]

1 + 2 = 3

K
www.xaraxone.com/FeaturedArt/kn/
www.klausnordby.com/xara

[wfcentral]

I am having a conversation with a co-worker about the properties of light on cylinders. Can someone please help clear this up? I have posted an image that I whipped up in Xara X to illustrate the two views. I know that the tops of the cylinders are not shaded correctly...I'm more interested in the sides.

The question is. If light is hitting a cylinder at a 45 degree angle, will the cylinder be evenly shaded top to bottom like the cylinder on the left or will it have a diagonal shade like the cylinder on the right??

Thanks,
Robert

[Clements]

Example 3

[Peter P.]

I just wondered how you could ever consider anything different...

[Steve Newport]

Mr. P, nice to see you back again, hope you had a Merry Christmas or chanuka or Kwanza, whatever you celebrate. BTW, Steve is fine for the salutations.

Just one little thing before I start my explenation, you quoted me saying...

[QUOTE]Originally posted by Peter P.:
Quote: "Originally posted by Steve Newport:
It depends "
QUOTE]

I only said "Depends", how bout you start reading!

Anyway, my explenation is quite correct. In both of my illustrations the light is coming from a 45 degree angle, Just in one case, the 45 degree angle light is not completely covering the cylinder. I made a picture for you just in case you're mind can't comprehend these words (See below)
Here, try it yourself. Hold a flashlight at a
45 degree angle over a cylinder (A cup or a mug, be creative) in a dark room so that the the edge of the light is at the center (Highth-wise) of the cylinder. You will see that the fall-off is, in fact, elliptical!

I hope you understand now!

Think before you speak Petie, you might not be held as such a moron then!

Roman, I'm not really seeing what you're saying!? Maybe I'm just stupid, I dunno!

And Gary, I have quite the same outlook as you. In art, what looks right is better than what is correct. Thanks

Steve Newport

[Steve Newport]

Although not expressed in my examples, your comment is 100% correct Bob and could be very usefull to everyone in here, especially Petey over there! Thanks for the tip!

Steve Newport

[Steve Newport]

If it's sunlight, then it would be your first example, even if it's not it looks good that way, so I think you're set! I'm assuming you're talking about the cylinder attached to the center of the wheel? Thanks for the Question!

Steve Newport

[wfcentral]

Boy, what a response we got on this thread. Sorry to see so many people get up in arms. Anyway, I thought you might like to see the type images we're creating in my office and why we were debating lighting. We are not concerned with the amount of light - we assume a daylight setting. We are more interested in the 3D look than whether it is clinically correct. I just need to illustrate to students so that they can tell whether a part is a cylinder or a flat piece of metal. The image below is part of a larger piece that goes into flash and becomes animated.

[Peter P.]

<BLOCKQUOTE><font size="-1">quote:</font><HR>Originally posted by Steve Newport:
It depends <HR></BLOCKQUOTE>

Wfcentral's question was, I quote:
"If light is hitting a cylinder at a 45 degree angle"

Maybe you should try to read next time.