I have read and re-read a thread here on CA about specular highlights and how to place them. David Briggs had some great explanations and diagrams about how to place them but I am still not getting it. If anyone can try explaining it to me in such a way that I can get it, that would be wonderful. Maybe some other examples besides utilizing spheres only. If David can maybe expand on it that would be great as well.
Thanks A Bunch,
I attached an example to show you what I am confused about. I roughly placed the horizon line and I estimated where the light is coming from by using the 3D arrow. Now in this particular example, the light is not coming directly from the front but neither from the side as well. Its between the two.
If I wanted to find out the location of speculars on the shoulders, chest, biceps and abs, I would have to imagine and tilt a seperate plane for each location?
If the light is neither coming from the front or side; in order to have the plane directly face me before I rotate it halfway back, I would have to rotate it on both axes no?
Remember when you said this?
(1) imagine a plane directly facing the light source, (2) imagine turning that plane on an axis [in the picture plane, and at right angles to the light fall] until the plane faces you
In the above example, if a plane was facing the light source, wouldn't I have to turn the plane on both its vertical and horizontal axis in order for it to face me perfectly?
I didn't say anything about the axis being horizontal or vertical; the axis is the line where the two planes intersect.
Please don't reply again until you have tried this out with an actual light source, a sphere and a mirror!
- Ok I tried it. But I'm not sure if I did it correctly. I used a compact mirror, my reading light and a shiny candlestick holder. I dont have any shiny spheres.
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It would help you to experiment and research light bouncing off spheres. Also look into something in 3D modelling called normals, they are the idea with the plane - little arrows that point away from the surface. You actually didn't estimate the light source correctly on the photograph, it's more to the left. You can see the specular highlights on the part of the body which faces an angle that's in-between the camera and the light source, usually.
I assume that these are the explanations you mean:
http://www.conceptart.org/forums/showthread.php/156556-Specular-Highlights?p=2234301#post2234301 http://www.conceptart.org/forums/showthread.php/156556-Specular-Highlights?p=2234783#post2234783 http://www.conceptart.org/forums/showthread.php/156556-Specular-Highlights?p=2235071#post2235071
Have you tried setting up a shiny object under a spotlight to see how the method works in practice?
The principle is exactly the same for non-spherical objects, the only difference is that the required plane is likely to fall on a plane break (corner) of the object, where the surface passes rapidly through a large range of angles.
I will try a setup. But I was wondering about the tilted plane that faces the light. As I go above or below the horizon line, does the plane that supposed to face the light, also change perspective? For example, if I am trying to utilize the plane technique on the head, do I have to re-orient the plane as I go down to the chest and legs?
Sure, as you work up and down the figure the plane facing the light source will be seen in changing perspective, and also the plane facing you will change in its absolute orientation, so to be really accurate you'd need to rethink the orientation at each level, especially for a nearby figure.
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