Join Steve Caplin for an in-depth discussion in this video Drawing the outline, part of 3D Print Small Objects with Photoshop.
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- Here's a photograph of another pawn from the chess set. What I'm going to do is to use the pen tool to draw the outline of this pawn. So, as always with a pen tool, you think, "Where do you start drawing?" Well, I know I want to get a vertical line that I'm going to revolve the outline around, so let's start at the top, right in the center, and I'm going to hold the shift key as I go down to the bottom of the pawn, and, right away, we've got a bit of an issue.
If I go over to the edge of the pawn here, you can see there's a curve on the photograph. I don't want a curved base, I want a completely flat base for this, because I'm going to have it flat on the table. So, let's hold the shift key down to make this horizontal, and click just here, so that it lines up with the edge of the pawn. Now, I can hold "Command" on a Mac, "Control" on a PC, and select both of those points by dragging over them.
I can drag them up, holding the shift key as I do so to keep my movement vertical, until this point now lines up precisely with the right edge of the pawn. Now I can release that key, click on that end point, and carry on drawing. Shift key again, to get this vertical. Now I can go into this corner, click and drag, to make that slight curve. I want a corner point here, so I can hold "alt" or "Option", and click on that, and that makes a corner point.
Let's go to the outside of this curve, and I can click and drag to draw a tangent to the curve, and now we can go all the way up here, click, and drag in the opposite direction. Now, as it turns out, this segment of the curve wasn't high enough, so it's easy to hold "Command" on a Mac, "Control" on a PC, just to pull that up and reshape the curve as we're drawing it. When I release the key, I can carry on drawing. "Option" or "alt" click again to make a corner point.
Back in here, another corner point, now I can go right up to the top, and start to draw my curve. Now, once again, we've got another problem because we've got this big overhang here. bearing in mind that the print prints it from the ground up, how is it going to print this overhang, when there's nothing to support it? And here, we can make two choices. We can either print this with scaffolding that supports it, that we than have to trim away, but that's a rather clumsy solution, because it will mean quite a lot of work, and it will leave a poor-looking raphe.
A better approach, I think, is to modify our drawing, so let's undo that last step. I'm going to instead stop roundabout here, and draw the curve for the body of the pawn like that. At this point, I'm going to "Option" or "alt" click it, to make a corner, and I'm going to come out at an angle, like this. So, we're going to get this very small neck underneath the horizontal part of the pawn, it's going to echo the one above, and that will mean that, as we print up, it'll print to this point, and then it can just step out gradually to print the whole of the top of the pawn, and I think that's the best solution.
Another corner point, and another. Here I want a curve to go around the edge of the pawn, so I can click on the edge and drag up, and there's our curve, and finally, to get back to the beginning, here I can click and drag to make the top of the pawn, and there is the path. We've had to compromise at this point, in order to make it more printable.
In fact, we could take a few risks with it, and maybe pick up just this point, and drag it up. I think it could still handle an angle perhaps as sharp as that. I wouldn't want the printing to be any sharper than that, because, remember, it has to print a small overlay with each layer as it goes up, but there, I think, is a close enough representation of our pawn to get a good result.