Creating a House

Level: Beginner

Goal: Learn basic skills for PEP modeling (editing points, edges, and polygons). Also learn how to change the appearance of a model by coloring vertices and specifying backface culling.

Assumptions: You should be familiar with the concept of PEP modeling. See PEP Modeling: Editing Points, Edges, and Polygons in the online help for more details. You should also be familiar with the Cosmo Worlds user interface. See A Quick Look at the User Interface for more details.

Finished product:

This tutorial consists of the following sections:

Use Undo and Redo to fix mistakes:


Creating a Roof for a House

The basic shape for a house is fairly simple.

  1. Start out with a cube in the PEP editor. Switch to hidden line so you can see the individual polygons easily (press and hold the right mouse button over your workarea and choose Draw Style > Hidden Line from the popup menu).

  2. Select the top polygon and press to split the top polygon lengthwise.



  3. Select the edge in the middle of the split polygon and Shift-drag along a side polygon to push the edge up and form the roof:

Creating a Dormer for a House

Use Split Buttons to Define the Dormer

You can model interesting shapes from a simple PEP object like a square by using a combination of split and cut operations, then extruding and moving the new polygons. Here's how to create a dormer from the basic house shape.

  1. Starting with the basic house shape in Example 1, select a side of the roof and press to split the polygon lengthwise:




  2. Select the lower half of the roof and press to split the polygon vertically:



  3. Keeping the same selection from step 2 (don't select anything new), press to split the quads like this:



  4. To make the angles for the dormer roof, select the appropriate quad and press or :



Now you have the basic shape for the dormer.

Extrude, Rotate, and Pull Out the Dormer

  1. To pull out the dormer, Shift-click to select the four polygons that make up the dormer. The last polygon you click becomes the master selection and is outlined in black:



    The master selection is used for aligning the front face of the dormer to the front face of the house. If you lose the master selection in later steps, you can reselect it by Shift-clicking the polygon twice--the first time deselects the polygon and the second time adds it to the selection and specifies it as the master selection.

  2. Move the dormer up and away from the rest of the roof. Make sure you have the correct polygons selected as described in step 1. Then press the Extrude Polygons button . Place the mouse cursor over the dormer and Ctrl-drag out, so the dormer moves away from the house and its edges are perpendicular to the roof.



    Next you want the dormer's face parallel to the front of the house. To fix the angle, you'll use the Snap Target and PEP Jack.

  3. Place the Snap Target by placing the mouse cursor on the front of the house and clicking the middle mouse button. A yellow arrow appears (see image in step 4). The target is used to align the master selection (specified in step 1) to the front of the house.

  4. Click the PEP Jack button and place the tool by clicking in the scene. Position the tool by dragging it. The PEP Jack doesn't need to be on the master selection or near it, but it does need to be positioned so the ring and green balls are in the same plane as the side of the house (see image below).



  5. Make sure the dormer polygons are selected and the master selection is specified (see step 1). Rotate the PEP Jack by dragging a green knob. The PEP Jack pulls the dormer face down. Drag the PEP Jack until the front of the dormer is parallel to the front of the house. Dotted lines indicate the master selection's alignment relative to the Snap Target; use this feedback to help you position the dormer correctly.




  6. Before the dormer is complete, you need to move it up so that it looks right. First, make sure the polygons making up the dormer are selected. Position your cursor over the front of the house, and Shift-drag up to move the dormer so that the bottom edges are aligned with the top edge of the polygon making up the front of the house. Again, use the feedback from the Snap Target to help you position the dormer correctly. Starbursts appear along the master selection to indicate its alignment.



  7. Take a moment to clean up your workarea; put away the PEP Jack and the Snap Target by clicking their buttons on the PEP and Layout palettes.

Creating and Opening a Door

Now that the dormer is correct, you want to create a door for the house.

  1. Click the Cut Rectangle button (on the PEP palette) and drag the cutting tool across the front of the house to define a new polygon for the door:



  2. If you try to select and move this polygon, it will pull out the points that define the front of the house. To move just the polygon that defines the door, select it and click the Chip Off Polygon button .

  3. The result is a polygon you can move independent from the rest of the house.

  4. Next, rotate the edge of the door like a hinge. Place the PEP Jack in the scene and align it along the edge of the door as shown below:



    Make sure the polygon making up the door is selected, then drag a green knob on the PEP Jack to rotate the door open.

Coloring the House

To color the house, use the Color Per Vertex Editor. This editor is pretty easy to use (for the basics, see the Color Per Vertex Editor quick reference). However, there's a trick to get the color of the roof separate from the rest of the house. Right now, each roof's side is made up of a single polygon that makes up the whole side of the house. When you try to color the roof, here's what happens:



Note: This image shows part of the Color Per Vertex editor next to the workarea. The model in the workarea is shown in Hidden Line draw style.

To color just the bottom square making up the side of the house, you first need to define the side polygon as two separate polygons. Click the Cut Polygon button on the Split palette. Click to define the first endpoint for the new edge and drag out a line, releasing the mouse button where you want to create the second endpoint. You now have a new edge that separates the side polygon into two polygons, separating the roof from the rest of the side of the house. Repeat this process to separate the roof on the other side of the house. When you color a side of the house, it should now look like this:

Looking Inside the House

Now that your house is colored, switch from Hidden Line draw style to As Is. (Choose Draw Style > As Is from the right mouse popup menu.) Notice that when you look inside your house, you can't see the inside of the walls or floor. To fix this, open the Normal Doctor and deselect the box next to Cull Backfacing Triangles.

  1. Select the house (you should not be in PEP Editing mode).



  2. Click the Normal Doctor button on the Looks palette:


  3. Click the box next to Cull Backfacing Triangles to remove the checkmark.

Now you can see the walls and floor inside the house.

That's it! For more information on any of these topics or tools, refer to the appropriate section in the online help.