On 3/24/07, Thorsten Wilms <t_w_@...123...> wrote:

On Sat, Mar 24, 2007 at 06:26:52PM +0100, Maximilian Albert wrote:

...

http://www.rzuser.uni-heidelberg.de/~malbert/

I don't get how you change from 2-point to 3-point perspective in the first 2 images.

The text explains it: "doubleclicking on one of the green PLs, which places the VP at the location where the click occurred"

The 2nd image is wrong, anyway, I think. The viewpoint would be above the box, as the top is shown slightly from above. The bottom must be farther away, then. So the VP for the vertical edges would be below, not above the box.

I don't see anything wrong with this one. It's an unconventional perspective but it's built according to the rules.

I guess in most cases with 2-point perspective, lines for the 3rd direction should be perpendicular to the horizon (has been a while since I learned and used this stuff - with the excpeption of quick hand-drawn approximations :)

All directions and VPs are freely draggable. You can set them to whatever you want. If you want to rotate everything, preserving the angles between the VPs and directions, just rotate the object by Selector tool.

1/2/3-point perspective should all be covered, IMHO.

And they are. You can freely switch any dimension from infinity VP to visible VP and back.

I think the VPs and horizon should be treated as rather secondary,

We don't yet have the notion of horizon at all, at least at this basic stage. Any pair of VPs can be taken to represent a horizon.

VPs, on the other hand, are very fundamental for this tool.

as the user will likely care more about the box. Because if you draw on paper, using construction boxes/lines, at least one VP would be far away from the paper in most cases.

So what? In Inkscape you can always zoom out as far as you need and still drag it freely.

The important things are the size and proportions of the box

Yes, for these we will also have handles to drag. They are just not illustrated yet :)

and the inclination of the edges.

And that is automatically determined from the VPs.

So I would like being able to move every corner, moving VPs implicitly.

When you drag a corner, you change the size/proportion of the box but its perspective (i.e. VPs) remains the same. When you drag the VPs, you change perspective but the box size/proportions remain the same.