Part 2: Creating a Rocket

In Part 2: Creating a Rocket, you'll learn how to model a rocket by using the PEP modeling tools. PEP refers to the individual points, edges, and polygons of an object. Editing PEPs in the PEP modeler is a powerful feature of Cosmo Worlds. As you'll see, a single shape can be modeled into a more complex creation.

After using the PEP modeler, you'll use layout tools to assemble the finished rocket ship.

Part 2 contains the following sections:


Starting Out

By now, you should have created a file called planet.wrl that contains a sphere with a texture applied so that it resembles a planet. If you haven't done this, see Part 1: Making a Planet.

If you have completed Part 1, continue here:

  1. If you still have Cosmo Worlds open from Part 1: Making a Planet, make sure you have saved planet.wrl. If you exited the program after finishing Part 1, then open Cosmo Worlds now.

  2. Create a new file by choosing File > New, then save as rocket.wrl.

  3. Import shipBasic.wrl, a file provided for this tutorial. Choose File > Import. Clear the Selection field, then type in this pathname and press Enter: /usr/share/Insight/library/SGI_bookshelves/Help/books/CosmoWorlds_UG/Models/shipBasic.wrl

    A cylinder appears.

  4. Hold your mouse over the scene and press the right mouse button to see the Viewer menu. Choose Draw Style > Hidden Line to see the model's segments:

Note: You can always undo a mistake by pressing Ctrl-z.


Adding New Sections to the Ship's Basic Shape

Your first task is to add segments to the ship's basic shape (a segmented cylinder). You'll do this in the PEP modeler, a mode for editing the points, edges, and polygons of a PEP object.

Jump to: PEP Modeling: Editing Points, Edges, and Polygons for more information on this topic.

  1. Make sure your are in pick mode (the arrow is selected on the viewing toolbar).

  2. Click the model to select it, then press the Convert to PEP Object button on the PEP palette:


    Notice at this point that most of the buttons on the PEP palette are grayed out.

    Note: If this button is grayed-out, the model is already converted. Go to Step 3.

  3. Click the Select PEPs button on the PEP palette to enter PEP editing mode:


    Notice that most of the buttons on the PEP palette (and the Split palette, if it's open) become available to you (they are no longer grayed out). An orange box appears around the cylinder to indicate PEP editing mode. PEP objects can be edited at any time by selecting them and pressing the Select PEPs button. If you click outside the orange box, you will no longer be in PEP editing mode.

    Shortcut: Select the cylinder and press Ctrl-e to enter the PEP modeler.

  4. Next, select all the polygons on one end of the cylinder. Reposition your view of the cylinder so that you can see its side (Alt-drag), then drag to form a box around the end of the cylinder. This is called sweep-selection.


    Drag the cursor to select endpoints.

  5. Reposition your view again so you can verify that all the endpoints are selected, and that you haven't selected other parts of the model:


    Verify that only the endpoints are selected.

  6. With the endpoints still selected, click the Extrude Polygons button on the PEP palette:


    Place the cursor over the side of the cylinder (as shown below), and Shift-drag parallel to the side to push up a new segment about the same size as the other short segments. Shift constrains the drag in a single direction and is indicated by a bi-directional arrow.


    Click the Extrude Polygons button and add a new, short segment.

    Notice the difference between extruding and moving selected PEPs (as shown above), and just moving PEPs by dragging them and not pressing the Extrude button:


    This is what happens if you forget to press Extrude--you enlarge the same segment instead of creating a new one.

  7. Add another short segment to the cylinder as described in step 6.

If you've followed the steps correctly, you now have a cylinder with one long segment, and four shorter segments:

The finished product for this section.

Terrific! You have finished adding segments. Next, you'll scale these segments to form the nose of the rocket. Take a moment to save your file before continuing.


Scaling PEPs to Create the Nose of the Ship

The next task is to make the ship aerodynamic, by scaling down the sections as they get closer to the nose of the ship.

  1. Make sure you are still in PEP editing mode. If you are not, select the cylinder and press Ctrl-e.

  2. Click over empty space to deselect all the endpoints (if they are still selected). Then click on the single point in the middle on the end of the cylinder (the same end at which all the endpoints were previously selected).

    put snap here
    Select just the centerpoint.

  3. Position the cursor over the top of the cone (the end with the selected point). Use Ctrl-drag to push the point out perpendicular to the end. Remember that in the last section, you used Shift to constrain movement in a single direction. The Ctrl key performs actions opposite to Shift.

    put snap here
    Notice placement of cursor. Ctrl-drag to pull out centerpoint.

    This cone is too sharp to make an attractive nose for the ship. In the next step, you'll round out the cone by scaling its points.
  4. Activate the PEP Jack, a tool for rotating and scaling points, edges, and polygons, by clicking its button on the PEP palette:


  5. The PEP Jack appears "stuck" to your cursor as you pass it over the work area. Drag the PEP Jack and click on the middle point of the cone you just created to place the PEP Jack there. Depending on how close you have dollied-in, parts of the PEP Jack might appear outside the PEP editing area (outside the orange box). Dolly-in closer to make all the parts of the PEP Jack appear inside the editing area (use the Dolly thumbwheel in the main window or use Ctrl-Alt-drag middle.

    put snap here
    Place the PEP Jack on the selected endpoint.

  6. Select all the cone's points by sweep-selecting (dragging a box around them).

    put snap here
    Drag around the cone to select its points.

  7. Click and drag on the small cube of the PEP Jack to scale the points into a more round shape:


    Drag end of PEP Jack to scale selected points.

  8. Repeat selecting and scaling all circles of points except the two nearest the back of the ship. If you'd like to save time, you can skip this last step. In the next section, you'll start out with shipConical.wrl, a file with the completed cone shape.

    the finished product snap
    The finished product for this section.

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