Learning speculum on form
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    Learning speculum on form

    I have a lot of trouble drawing specular objects. Should I order some metal balls off Amazon?

    Anyway, I tried to tackle it by drawing a gynoid (torso is a bit off). I used a toy car for reference. The helmet is supposed to be specular and black in color. Boobs and belly is matte black. The rest are glossy white. The light is coming from the back, as denoted in picture.

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    what the heck is going on in her abdominal and crotch area?? this is just...well, wrong. sorry i can't give you more, but there's just so much to say about it and its late, so when i'll wake up i'll try to elaborate more if needed. but do peek up some good reference of female anatomy.. even if you are going for the stylized look it should be based on correct one...

    as for the lighting - right now your main light source seems to be coming form right (ours) front, not from behind her (as i understood from your post, but it may be just that i misunderstood the "coming from the back" thing).

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    Quote Originally Posted by Noa K View Post
    what the heck is going on in her abdominal and crotch area?? this is just...well, wrong. sorry i can't give you more, but there's just so much to say about it and its late, so when i'll wake up i'll try to elaborate more if needed. but do peek up some good reference of female anatomy.. even if you are going for the stylized look it should be based on correct one...
    I did that to the stomach on purpose, I tried to make it look weird, hehe. "She" is not fully human anyway, so the anatomy shouldn't be too much of a concern at the moment. So the light is actually coming farther to the right, I will move the light source farther to the right then. I drew an elliptical light to show it is at an angle, and I unknowingly shaded as if the light was farther to the right. I will fix that.

    Last edited by Vay; July 9th, 2011 at 11:07 PM.
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    you arent seeing the light to dark ratios correctly yet. get some better ref; before the specularity the black and white should retain their general color and values.

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    Quote Originally Posted by dpaint View Post
    you arent seeing the light to dark ratios correctly yet. get some better ref; before the specularity the black and white should retain their general color and values.
    The picture is just a photo of the toy car I own. I have problem with specular objects, and I don't know how to render it at all. So I just look at the toy car and see how that goes. But I think I know what you mean; the darkest value of your lights should not be darker than the lightest values of your darks, right? Just learned that from Noah Bradley's environment video, what a coincidence.

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    Essentially that is correct except in extreme cases they will overlap and this is an extreme case. The problem is you have very reflective surfaces which most likely will have a full range of values. You need to preserve their color appearance while making them look shiny. If you have a black shiny object and a white shiny object the only difference is the white and black of the shiny objects so make sure you preserve that.

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    Here is new edited version:

    I have a lot of trouble placing the specular highlights and defining their shapes.

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    Last edited by Vay; July 12th, 2011 at 10:42 PM.
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    Quote Originally Posted by Vay View Post
    But I think I know what you mean; the darkest value of your lights should not be darker than the lightest values of your darks, right? Just learned that from Noah Bradley's environment video, what a coincidence.
    That rule only applies for matte, opaque surfaces. The rules of light on reflective surfaces are totally different, which is why they're so hard to invent. On a fully reflective surface, the surface is a mirror of the environment around it, so the values totally depend on the surroundings. Check out M.C. Escher's Three Spheres:
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    A crystal ball (reflective and transparent), a mirror ball (reflective and opaque), and plain white ball (matte and opaque).


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    Jim has a couple great posts on this as well: Reflectivity and Checkerboard Illusion.

    He goes into more depth on the Checkerboard illusion in "Color and Light", page 48, Chapters 1-7, Verses 9-21. Amen.

    Edit: Oh, and just for, you know, future reference..."speculum" is very different than "specular"...though speculum may be appropriate in context with a gynoid.

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    You cant just go half way Jeff !! the definitions of speculum are:-
    1. A mirror or polished metal plate used as a reflector in optical instruments.
    2. An instrument for dilating the opening of a body cavity for medical examination.
    3. Zoology
    a. A bright, often iridescent patch of color on the wings of certain birds, especially ducks.
    b. A transparent spot in the wings of some butterflies or moths.

    as for Gynoid ?? do you mean a Gynacological female robot !? I am not sure where you are going with that one matey, it seems dodgy ground through man!
    Mind you looking at Mrs bury me in a Y shaped coffin up there if form begats function I think a light glimmers ha ha ha ha

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    Ha! Vay actuallycalls her a gynoid in the OP...and originally a term coined by Hajime Sorayama I believe. But thanks for the thorough definitions! Didn't know it referred to iridescent wings patters too.

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    Very interesting that this comes up right when I'm studying a tea kettle....been wondering about specular surfaces myself lately. Good information in this thread.

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    Damn Jeff you got me again !!! LOL I didnt know any of it mate I looked it up!

    Vay :
    As for the image I think with a bit more spit and polish it could look very interesting, but those hips really are freaking me out though, is there anything you can do with them or anything you are willing to do with them?

    all the best with it anyway matey

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    Specular/shiny/reflective surfaces tend to have very abrupt, extreme value changes, as opposed to the gradual transitions of value found on more matte surfaces. One important thing to keep in mind is that those abrupt changes very closely follow the forms and are important in defining the form accurately. The vehicle example in Jim's "reflectivity" article is a good example...as are the helmets dpaint posted.

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