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Rebeccak
02-13-2007, 09:15 PM
*Please note that the 3D female figure is by mashru.

Taking the above simple examples further, let's look at a 3D model of a head and figure (as generously provided for free by mashru (http://forums.cgsociety.org/showthread.php?t=446213)).

Below I've taken mashru's model and screencaptured it and a cylinder with a proximal position in space from varying perspectives to illustrate the cross contour lines of each in space.

In each of the images below, look at the horizontal lines to analyze how they curve either upward or downward depending on where the eye level of the viewer is relative to the figure and the cylinder.

Also, analyze the spacing of the horizontal lines relative to one another and the vertical lines relative to one another to see how the spacing grows or shrinks depending on whether the form is extending or receding into space.

Finally notice how these horizontal and vertical lines literally map the surface of the form - the images below are 2D screen captures, yet because the horizontal and vertical lines follow the topology of the form, they create the illusion of dimensionality. This is the goal of a cross contour drawing:

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_001.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_002.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_003.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_004.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_005.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_006.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_007.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body-Cyl_008.jpg

Rebeccak
02-13-2007, 09:44 PM
Now look at and analyze these screencaptures of the model alone and analyze the form based on horizontal and vertical line proximity and direction (upward curving or downward curving) of the horizontal and vertical lines. Ask yourself, how are these lines creating the illusion of form and dimensionality?

Note how the horizontal lines above the viewer's eye level curve upward, and those below curve downward.

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body_001.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body_002.jpg

Note that there are no downward curving lines here, because the viewer's eye level is below the entire figure:

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body_003.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Body_004.jpg

Rebeccak
02-13-2007, 09:51 PM
The above images are meant only to illustrate the concepts of perspective that are crucial for an understanding of a cross contour drawing. This is not a 3D tutorial, but a 2D drawing tutorial which is meant to help you to describe 3Dimensional form on the page.

Elements of a cross contour Drawing

There are a number of different formal visual elements which are important in a cross contour drawing:

Line weight / pressure / contrast of lines

Line spacing / proximity

Line direction

Line weight and contrast comes into play especially - a lighter line recedes, while a thicker / heavier line comes forward in space.

Line spacing, as we have seen illustrated above, determines how close to the viewer a particular area of the object is - the nose, for example, protrudes further from the face than the lips in a front view, so the line spacing would be greater on those areas of the nose closest to the viewer. By contrast, where the cheeks begin to recede back toward the ears and edges of the face, the cross contour lines would be spaced more closely together to indicate their recession.

Line direction (upward facing or downward facing lines) determines how the viewer's eye level is shown - lines above the viewer's eye level with curve upward, while lines below the viewer's eye level will curve downward.

Rebeccak
02-13-2007, 09:56 PM
And now, for the embarrassing part - some self portraits / cross contour drawings done for my class. These drawings are far from perfect, but I hope that they are illustrative of the concepts described above and I highly encourage you to try them.

The main thing I recommend is to draw from life when doing these. The assignment I had is to do around 8 of these cross contour drawings in a week. Doing this exercise, as fundamental as it is, has really helped me to perceive things better and to look more closely at the subject at hand, as well as to better analyze it.

30 minute contour drawings:

http://anatomy.cgnetworks.com/15%20Minute%20Sketch/Sketchathon-011.jpg

http://anatomy.cgnetworks.com/15%20Minute%20Sketch/Sketchathon-014.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Drawing-003.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Drawing-002.jpg

After doing these ballpoint pen cross contour drawings initially, I decided to try and incorporate the cross contour drawing concept into my charcoal drawings, which I believe has made a difference. These are drawn from reference:

Untimed:

30 minutes:

30 minutes:

Rebeccak
02-13-2007, 10:04 PM
Finally, here are some more screen captures of the head model by mashru (http://forums.cgsociety.org/showthread.php?t=446213) to further illustrate the cross contour lines of the head.

One thing to note about the difference between the wireframe of the model used and drawing cross contour lines is that mashru has modeled the figure to be animated, so the wireframe topology is a bit different in some places than how you want to draw your cross contour drawing.

When drawing, think of each line as a slice of the figure - don't encircle areas (such as the mouth) which is something in the 3D model which is done to make it better to animate - instead in your drawings, make the lines continuously either horizontal or vertical, but following the topology of the form - sort of as though you are skiiing over it in either direction.

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_001.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_002.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_003.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_004.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_005.jpg

Rebeccak
02-13-2007, 10:04 PM
http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_006.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_007.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_008.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_009.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_010.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_011.jpg

http://www.rebeccakimmel.com/gallery/albums/Cross%20Contour%20Tutorial/Cross-Contour_Face_012.jpg

Rebeccak
02-13-2007, 10:07 PM
Cross Contour Drawing Exercise

I really recommend trying this exercise for those who haven't, or for those who haven't for years. ;)
Working from life only, draw at least 5 - 10 timed cross contour drawings of a head / face - your own or of someone you know. Do at least 5 in one week.

Use 4B or 6B sharpened pencil in a sketchbook which is at least 12" x 12" in dimension.

If you time your cross contour drawings, give yourself 30 minutes for each.

*Note that the 3D illustrations are just that - illustrations - this is a 2D Drawing Exercise.

I hope this is useful. Please feel free to post your work here! :)

Cheers,

-Rebeccak

anandpg
02-14-2007, 03:50 AM
Hi Rebecca!.. This is really helpful! thanks.:) I will try and draw from 3d Models(I dont have access to live models right now) to post here.

Rebeccak
02-14-2007, 01:18 PM
Thanks anand! :) Actually I really recommend doing self portraits - though I've tried the method using Sketchathon reference, and that is helpful as well, I think you'll most definitely get a stronger drawing using yourself as reference or a friend.

Sketchathon reference is here (http://forums.cgsociety.org/showthread.php?p=4191662#post4191662) (NUDITY):

Miyagu
03-04-2007, 03:29 PM
Lovely drawings Rebecca! Inspiring to look at.. really "fleshy"..

paintdabs
03-06-2007, 08:33 PM
Hi Rebecca, I'm finally checking out the forums, etc here and came across yours. I have a lot of baby steps to take, but am inspired and edified by all the terrific artists here.

Rebeccak
03-06-2007, 08:50 PM
Benita, you changed your name! Thanks for stopping by. :)

Dorothy, good to see you on the boards, and look forward to seeing your participation around here! Feel free to start up a Sketchbook in the Sketchbook area, would be nice to see your work. :)

su
07-06-2007, 02:16 AM
Thank you Rebecca for the tutorial and Mashru for the model used in the illustrations :)

That seems to be a pretty good exercise, and it would also be helpful to draw with contours if you are going to shade your drawing.

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