Imagine Tutorial

We touched upon the "Mold" tool last month, as a way of
creating interestingly shaped objects. Let's now look at the
various Mold options in slightly more detail. Thankfully
none of them deal with a greenish fungus, rather they
control how a primative shape can be warped into something a
great deal more useful.

Using Mold is always done in the same way. First of all, in
the Detail Editor, create and highlight an object. Then use
the Mold menu option (from the Function menu) or press
Amiga-E. This will bring up a list of the various options.
Here they are in more detail.





1. Extrude

(im10_1.iff)

Extrude will stretch out the object, creating a new solid.
It has several options which can make a huge difference to
how the new object appears. As we saw last month, the
stretched component can follow a Path to create weird curved
objects, or it can stretch in a straight line "Along
Length." The rotation, scaling and translation settings
define how the object should change over its length. Here
are some examples.


a. No rotation, scaling or translation makes the square
plane into a solid box. Remember to switch off Phong shading
in the object attribures to avoid the edges being curved.

im10_2.jpg

b. Applying scaling values of 0.1 causes the square to
shrink as it extends, and this causes it to become a
pyramid.

im10_3.jpg






2. Replicate

(im10_5.iff)

Replicate is very similar to Extrude except that the new
obect is not solid. Instead, multiple copies are created (by
default, 5). This gives the effect of slices as you can see.

a. Altering the scaling causes the slices to change in shape as
they move away along the length of the original flat object.

im10_4.jpg

b. If the rotation value is set, the slices can be made to
spin as well as deform. Try this with solid shapes to make
bizarre linked chains of objects.

im10_6.jpg





3. Spin

(im10_7.iff)

Spin works differently from the first two effects, and
rotates an object around it's Z axis. It's useful for
creating complex shapes which are symmetrical. For example,
think of a lathe creating objects from wood: this is how the
spin tool workds.

a. Applying Spin to our square doesn't produce anything
particularly interesting as it simply folds up around
itself.

im10_8.jpg

b. Applying Spin to an outline object (see box out) makes
for a more interesting shape. Spin makes objects solid, and
does something annoying with the last point, so isn't the
best for glasses or bottles.

im10_9.jpg





4. Sweep

(im10_10.iff)

Sweep looks like Spin, but keeps the object hollow. It is
therefore perfect for glasses, bottles and other objects.
Once you master this technique you'll use it again and
again.

a. Here's the glass object, this time using Sweep rather
than Spin. It looks a lot better I think you'll agree. 12
slices should be enough for most objects.

im10_11.jpg

b. Here is the same glass object, this time rendered in more
detail with some attributes set.

im10_12.jpg

(im10_13.jpg -- larger and more detailed for anywhere you
need an illustration)







Box out: Making Outline Objects


Here is how to make an outline object for use with Mold
tools such as Spin and Sweep. You are effectively making an
object from nothing, so you have a large degree of control
as to what the finished object will look like.

step 1 : Create an Axis

Every object must have an Axis, so use the menu option ADD
AXIS to create one.

im10_s1.iff

Step 2 : Draw the outline

Make sure the axis is selected, and then pick "Add Lines"
from the Mode Menu. Now draw out your outline.

im10_s2.iff

Step 3 : Process the outline

Change back to "Pick Groups" and the outline will appear.
Now you can use Mold/Spin on it to create your object.

im10_s3.iff








Box out: Sweeps with an Edge


Here is how to make a shape which is hollow, but also has a
thickness of it's own. It looks rather like an inkwell or a
small pot when it is finished.

1. Create an axis, and use Add lines to draw an outline.
Make the outline double back on itself, like his.

im10_14.iff

2. Apply a Sweep (not a Spin) to keep the shape hollow. The
default factor of 12 will suffice.

im10_15.iff

3. The object will be created. Notice how it now has an edge
which is quite thick, and yet is still hollow.

im10_16.iff

4. Adjust the objects attributes and render. Here I have kept
the Phong setting on to keep it smooth.

im10_17.iff


 
Box out: Halfway Sweeps

Sometimes you don't need to make an object sweep round to
become a closed shape. For example, here is how you could
make an Edam cheese with a slice missing.

1. Create an axis and sketch out the outline of the cheese.

im10_18.iff

2. Apply a Sweep, but this time alter the 360 setting.

im10_19.iff

3. Notice how there is a gap in the object now.

im10_20.iff

4. Render the object. I created two objects, one white and
one red to produce the effective cheese appearance!

im10_21.jpg


(im10_22.jpg -- weirds image for whatever use you like)

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