|Build a Personal Spacecraft
in Amapi Designer 7
Carl E. Schou
June 31, 2003
The Teeth of
Have you ever had the urge to take an
early morning flight, skimming over the clouds of a distant world
in your own custom built, personal spacecraft? Well, getting
to the distant world is up to you, but you can create the craft in
Amapi, and that's the subject of this month's foray into the
We will start
with a brief overview of Amapi, followed by a summary of the
modeling strategy for this project before we begin the actual
For anyone not
familiar with Amapi, the workspace is split into three rooms for
Modeling, Rendering, and Cataloging your work. All of our
work for this tutorial will be done in the Modeling room.
The tools in the Modeling room are arranged into a Basic Toolkit
and into three Tools Palettes. The Basic Toolkit includes
functions like Move, Rotate, Scale, and Stretch. The
Construction Palette includes Surface and Volume
Primitives, Sweep, Double Sweep, and various surfaces. The Modeling
Palette includes tools such as Smooth, Chamfer, Thickness, Cut,
and Tesselate. The
Assembly Palette includes tools such as Duplicate, Symmetry, Weld, Snap,
Decimate. This is just a partial listing of the tools
available in Amapi. Most of these tools are outside the scope of this
tutorial and are well covered in the Amapi PDF manual.
Extrude/Sweep tool is found in the Construction palette. The
definition and operation of these functions vary enough between
different 3D applications that is it worth covering Amapi's
implementation here. The Sweep is accessed by clicking on
the symbol of a curved pipe in the Construction palette.
This will open the pop-up options menu shown above. Clicking
Extrude allows you to extrude a facet straight out (perpendicular)
from the original facet's position, in the direction of that
facet's normal. Clicking Sweep allows you to change the
orientation of the facet as you go. In addition, you can
select three different types of sweep and use the space, shift and CTRL
keys to control the amount and direction of scaling and growth. If you
haven't used these functions before, the explanation probably
sounds a lot more complicated than it really is. The tools
are very intuitive to use.
(1) Build a simplified low polygon model using Box
Modeling techniques. Start with a box and extrude, sweep, and
stretch it to get the
overall desired shape.
(2) Apply smoothing to the model.
(3) Adjust vertex
positions to get the final desired shape in the smoothed mesh.
(4) Split the model into
groups for ease in texturing later on.
Low Poly Model with Box Modeling
Box modeling is simply the technique
of taking a box, extruding and sweeping the faces, then scaling
and moving the parts to roughly approximate the object you want to
model. This simplified model is then smoothed through
subdivision to produce the final high resolution mesh.
To simplify things, you can turn off
the Dynamic Geometry feature for this project. If you prefer
to work with Dynamic Geometry turned on, you will need to turn it
off or collapse it when you start using the Stretch tool on the individual
vertices of the model.
To begin, click on the Surface and Volume
Primitives icon in the Construction Palette and select the
cube. Make sure you are in Poly mode. Click in the Top view window and drag to create
the cube that everything else is going to grow from.
Click on the size icon. In the
pop-up window that appears, uncheck the prop size button, then set
X = 12.2, Y = 3.4, and Z = 20.2. The resulting Front and
Perspective views are shown below.
||Select the two
side panels of the box, click on the Extrude tool and press
Enter. Choose Sweep mode and raise the extrusions as shown
below left. You may need to press the space bar a few times
to get the desired type of sweep. Then hold down the CTRL key and adjust the
extrusion size as shown below right.
extrusion process to build the wings as shown in the Front view in
the image below. There were eleven steps of Sweeping
(indicated by an "S") or Extruding (indicated by an
||Switch to a
Top view as shown below. Determine which points need to be
moved to give the wings the shape you want. Select these
points and click on the Stretch tool from the Basic Toolkit. Tap the space bar
several times to constrain motion to the axis you want to move the
vertices in, then start shaping the wings. To keep things
symmetrical, select and move vertices on both wings at once.
||In the image
below, the wings have been swept back a bit.
||Finally, a few
vertices were selected and pulled far forward.
below illustrates the four steps in the construction of the
The top center facet was selected.
This facet was Swept out and forward,
and shrunk a bit
The facet was then Extruded inward
and shrunk a bit more.
The facet was Extruded outward and
shrunk still further.
Extrusion process was used to build up the nose of the craft as is
shown in the Top and Side views in the image below. The
front facet of the box was selected and Extruded out, then in,
then out, then in, then out. Each extrusion was shrunk a bit
to taper the nose.
facet of the nose was selected (as shown above), and then Tessellation
was applied to produce four facets (as shown below). These facets were
Extruded to start the modeling of the guns.
extrusions of the guns may be seen in the images of the almost
finished model below.
Click on the
Smoothing icon from the Modeling palette and accept the default
Catmull-Clark subdivision algorithm. In the Parameters
window, set Range to 3. Swipe the cursor to the right to
validate the changes.
To make life a lot easier later on,
it is a good idea to split the model into groups. This will
let you apply different textures to the various parts of the
model, using either image maps or procedural textures. The model may be
grouped using the UVMapper utility or the Grouping tool in Poser, but you can
also do this work right inside Amapi.
do the grouping inside Amapi, select the facets to be included for
a given group. In the Modeling Palette, click on the Cut
tool, and choose the Extract option. Double click the selected
area to extract it, then double click it again to open the
Information pop-up to rename the group. Repeat this process
for each group. Click on the Group tool, then click
"A" to lock all of the parts together.
this project, the model was split into separate groups for the
hull, the canopy, the sections of the nose, and the parts of the
guns. The model was then exported in the WaveFront OBJ
format, ready for texturing and rendering.
The Rest of
The grouped model was
imported into Bryce where procedural textures were applied to each
group. The rocky crags jutting through the clouds are
terrains with height dependent transparency mapping applied, so
that the bottoms of the terrains fade away into nothing. The
cloud cover was made of a volume cloud slab and a cloud
plane. Torus shaped volume clouds were also added around the
peaks. The sky was made by starting with one of the defaults
and tweaking it a bit in the Atmosphere Editor of Bryce's Sky Lab.
until the next time. I hope you enjoyed his project as much
as I did.
yeah, don't forget to buckle up.
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Copyright © 2003,
Carl E Schou, All Rights Reserved