What exactly is meant by additive construction and why does cutting back make things look flat?

1:26 PM, Tuesday June 16th 2020

So I've just read the Lesson 3 leaves exercise, and it says that we must use additive construction instead of cutting back. What exactly does it mean when you "cut back" on something you've drawn? Does that mean like, say, adding holes, or removing a portion of something you previously drew? If so, why does this reinforce us to think more about flat shapes? I don't understand.

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3:41 PM, Wednesday June 17th 2020

This concept is actually a lot more relevant when you get into later lessons, but basically what you want to avoid at all costs is interacting with your drawing as though it is just a flat, two dimensional thing. Every change you make to it must be done keeping in mind the notion that you're interacting with something three dimensional. With leaves, this is harder to explain for the same reason that it's harder to do wrong - leaves themselves are flat, so there's a lot more you can get away with.

Where it starts to become a serious problem is when you get into more solid, organic and geometric forms. Cutting across a form's silhouette as though it's just a shape on your page immediately reminds the viewer that they're looking at a flat drawing. Instead, whenever we manipulate such a form, we need to always run our cuts along that form's surface, constantly reinforcing the illusion that it's 3D rather than undermining it.

Especially earlier on, it can be difficult for students to really understand the difference between cutting back into the 3D, physical leaf that they're drawing, or cutting back into its 2D silhouette on the page, so for now I recommend that students try to primarily create things like ragged, spiky edges by adding bits onto the form itself, rather than cutting back into it.

Here's a more visual explanation of what it means to apply subtractive construction correctly and incorrectly in organic and geometric forms: https://i.imgur.com/qVQXfIY.png

2:42 PM, Thursday June 18th 2020

I really like that explanation about separating one form into two 3D forms using contour lines. Reminds me a lot of form intersections but applied to organic forms instead.

It's like there's a common surface between the two new forms which also happens to be where they touch. Along the surface of the original form that contact surface shows up as a contour line. It all makes so much sense.

11:35 AM, Friday June 19th 2020

I'm sort of understanding it a bit better than before. Although, I have one question, if you wouldn't mind answering. When you say to primarily add bits onto form rather than cutting back into it, does that include the way you cut back into the bottom edge of the leaf example under "Zigzagging edge detail", because although you've cut back into them in your drawing, in 3D space, the edges are actually being lifted up?

So is cutting back pretty much when you only want to show how a form can be divided, rather than how it's moved in 3D space? Thanks for the reply by the way.

8:33 PM, Friday June 19th 2020

Yeah, with the zigzag one I do mention there that while it is physically just cutting back in terms of the 2D drawing, we actually understand it those edges being lifted into space. So the reason it works is that we're not actually trying to capture the impression that there's pieces cut out of the form - we're still manipulating it in 3D space, and we're entirely aware of this as we do it.

It largely comes down to what we think we're doing as we do it. If we're not taking the time to think about how our alterations change the 3D construction, then we're more likely just trying to alter the drawing as it exists in 2D space only.

10:15 AM, Sunday June 21st 2020

I see now. It is important after all to think in 3D instead of 2D when we're drawing.