| This tutorial
explains how to construct 3d cubes using 3 point perspective.
It assumes you have basic knowledge of Paint Shop Pro and vectors.
While this tutorial uses vector lines, it is for convienience
only, and the same effects can be reproduced in any graphics
editor that supports straight lines. |
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| 1. |
Create a new image (1000x1000 pixels) with a white background
in Paint Shop Pro. Create a New Vector
Layer, and call it "Left Vanishing
Point". |
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| 2.
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Select
the Draw tool  ,
and in the Tool Options - Draw
dialog box select Point to Point line,
width 1, Antialias
and Create as vector checked, and
Close path unchecked. Select the
color black for the foreground stroke style, and no
fill 
for the background stroke style. |
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| 3.
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Draw
4 lines from the top left of the picture to the bottom right.
Make sure these are straight. It helps if they fan out like
in the example. |
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| 4. |
Select
all four lines with the Object Selector
tool  .
Align all four lines to the Top
and Left using the menu Objects->Align....
They should all now start at a common point (vanishing point),
and this point can be moved around using the upper left resize
handle  .
Move the vanishing point to the top left corner of the picture. |
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| 5. |
Create
a New Vector Layer and call it
"Right Vanishing Point".
Copy (ctrl-C)
the four lines to the clipboard.
Paste (ctrl-G)
four more lines into this layer. Mirror
(ctrl-M) the four lines, and move
the vanishing point to the top right corner of the picture. |
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| 6. |
Create
a New Vector Layer and call it
"Lower Vanishing Point".
Copy (ctrl-C) the four lines to
the clipboard. Paste (ctrl-G) four
more lines into this layer. Flip
(ctrl-I) the four lines, and move the vanishing point
to the lower middle of the picture. |
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| 7. |
Where
these three vanishing points are arranged determines the viewpoint
of any cubes you construct later on. For this tutorial try to
position the Left and Right
Vanishing Points in each respective top corner of the
picture and align them horizontally. Position the Lower
Vanishing Point in the lower middle, so that all three
points form an upside down isoceles triangle.
Of course, feel free to later experiment with different arrangements. |
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| 8. |
Now,
because of the way all the lines are arranged, it should be
possible to change the end of each line (without moving its
other end from the vanishing point) by simply selecting it with
the Object Selector tool, and dragging
the resize handle closest to the end of the line. If you do
have trouble finding this handle, you can also select the line,
right click and select Node Edit
and drag the correct node as desired. |
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| 9. |
In
the Layer Palette dialog box, expand
all three layers by clicking on the small box with a plus on
it, and this will display all the "Drawing"
objects in these layers. In each layer toggle the Object
Visibility
to "off" for each "Drawing"
object except the first one from each layer. This will leave
only three lines visible in the picture. |
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| 10. |
Using
either technique discussed in Step 8,
position all three lines so that they cross at one common point.
This point will be the closest corner of the cube to the observer.
Select each line, right click on the selection, and select Properties.
Re-colour the line coming from the "Lower
Vanishing Point" green, and the others to red. |
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| 11. |
Turn
the visibility on of one line in each of the three layers,
so now there should be six lines visible in the picture. Position
these so that they cross at a common point, somewhere above
the first point. This will be the back corner on the top of
the cube. Re-colour these three lines red. |
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| 12. |
Turn
the visibility on of the two remaining lines in the "Lower
Vanishing Point" layer. Position these lines so
each one crosses the points made by only two other lines. Re-colour
them red. |
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| 13. |
Turn
the visibility on of one line in each of the "Left
and Right Vanishing Point"
layers. Position these so that they cross the green line at
a common point, somewhere below the other points. Re-colour
these lines red. |
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| 14. |
Turn
on the visibility of the last two lines. These should be positioned
so
each one crosses the points made by only two other lines, and
in doing so they should also form another point in the middle. |
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| 15.
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Now
you have constructed a wireframe cube that can be traced over
with more vector lines, or coloured and textured.
If you are interested in colouring and texturing please read
the next tutorial - 3d Texturing. |
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Finished
result.
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| Note:
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This
tutorial provides one of the many different ways to construct
3d objects in 2d space. It is lengthy and often difficult and
confusing. This is no surprise as it is trying to bypass the
complicated geometry involved in 3d space.
There are numerous 3d graphics programs available around the
world, and they can all acheive much more reliable results,
but hopefully you gain more satisfaction being able to claim
that it was "all your own work".
Also, you may find that positioning the vanishing points in
certain places produce cubes that don't look "right".
Ideally, if you can imagine the vanishing points in 3d, they
should form an orthogonal set (that is, a line from the viewpoint
to a vanishing point is perpendicular to any other line from
the viewpoint to a different vanishing point). The mathematics
gets tricky, and your best hope is to play around until it does
look "right". |
written
10th december 2001 by youp
|
3D-CUBES
TUTORIAL 
