Study Journal: 08_June_2014 - Matte Surface Rendering and Shadow Plotting

I'v been working through more of Scott Robertson's Gnomon DVD's, mainly the Basics of Perspective and Matte Surface Shading (Planar) ones. I'm finding the techniques extremely useful for solving many of the problems I have when trying to draw things correctly (perspective, lighting etc.)

This weekend i've been studying the Matte Surface Shading lesson and learned about the Half-way to Black value assignment technique. It's a good starting point for learning how to decide how dark and light the different planes of a surface should be.

Assigning Values

Main things I learned:

• 1,2,3 Read is important.
• Form Change = Value Change
• The darker a surface is the less light bounces off of it.
• Light bounced onto surrounding surfaces is also tinted to the colour of the surface the light is reflecting off.
• The gradation of bounced light on surfaces has to be extremely smooth to avoid the value change looking like a form change.
• The brightest surface of an object is one that is closest to perpendicular/90 degrees to the light source. 

Plotting Shadows

Notes:

• Shadow construction is made up of 3 main components: Light source location, length of shadow and direction of shadow.
• Because the sun is so far away, it's light rays are almost parallel when they reach the earth. Meaning they all can recede to one point.
• When front lighting objects you only really need to determine the shadow vanishing point, wherever you feel the shadows should recede to and then drop the sun in 90 degrees to that point below the horizon line.
• Side lighting is the same: if the scene is directly side light though, the shadow direction can be parallel to the horizon and the light rays can be completely parallel to each other.
• Diagonal lighting provides the strongest 1,2,3 read + a good cast shadow out of all the possible lighting strategies.

I think i've learned enough of the very basics to start practicing applying all of these techniques on my own for a bit before I move onto more complex techniques.

Note: I understand that these posts won't be interesting to anyone apart from myself but I feel it is really useful for me to journal my "boring" study stuff, so I can keep better track of what i'm learning and so I can collate any notes/thoughts I have on it in one place.