|Category ||New Users |
|Time Required ||20 minutes |
|Tutorial File Used ||vacuum_part2.wire (updated in the Get started lesson) |
Designs in Alias start from curves and surfaces. This lesson focuses on creating surfaces and understanding the relationship between curves and surfaces, and how Construction History can assist the design process.
In this lesson, you create and evaluate the initial surfaces for the vacuum. This lesson also introduces Construction History and basic organization skills.
- Understand relationships between curves and surfaces.
- Use visual symmetry
- Visually evaluate curvature
- Modify surfaces using Construction History
- You have completed the Get started lesson.
Create the initial surfaces
With the curves placed according to the sketch, you can create surfaces for the top of the vacuum. The curves are linked through Construction History to the surfaces, allowing easy adjustment later on.
- In the Layer Bar,-click the motorbox layer and choose the submenu item . The initial motor and dustbin shape is only needed for reference as you build further surfaces.
- Press ++ (Windows), or ++ (Mac) to Tumble to a view of the scene.
- In the Layer Bar, click the visibility square to the right of the name of the"mageref layer to hide all of the image reference in the scene.
- Create a topsurfaces. , make it active, and rename it to
It is a good practice to put curves and surfaces on separate layers.
- Choose .
Double-click the icon to open the tool options.
- Set 1, and to 1. This creates a surface by sweeping a single curve profile along a single path curve. to
While the Rail Surface options dialog is open, the prompt line says Select generation curve. The tool is active when its options are being edited.
- Pick the central curve as shown.
The curve becomes highlighted and the prompt line says Select primary rail curve .
- Pick the front curve that arcs over the motorbox.
The rail surface is created, and the tool remains active.
- Pick the central curve again for the next generation curve.
NoteDue to coincident curves and edges, a pick chooser appears under the cursor when clicked.
From the pick chooser menu, select "curve#4" (the # may be different) to pick and highlight the original curve.
- The prompt line says Select primary rail curve . Pick the back central arc for the rail curve. A second surface is created. , then to avoid starting another rail surface.
- Press ++ to bring up the display marking menu and drag to the right to select .
The actual surfaces are easier to see in shaded view.
- the model as vacuum_part3.wire.
Use display symmetry to show continuity
The goal of modeling only one half of the vacuum is to simplify the process, but take care that the halves line up and appear as a single object when finished. Symmetry and visual analysis tools assist in making adjustments.
- -click the topsurfaces layer in the Layer Bar, and choose from the context menu. This activates visual symmetry for all contents of the layer.
By default, the symmetry display shows symmetric geometry across the X axis. By setting up the sketches and curves so that the center of the vacuum crosses the origin along the X axis, this default symmetry is useful for previewing what the other half of the model would look like.
- Use the shading preset near the bottom of the to evaluate the continuity of the symmetric surfaces.
The alternating black and white lines (also called "zebra stripes") do not meet as they cross the centerline.
This indicates that the curvature of the surfaces is not continuous. When the halves are later connected, they should form a visually continuous surface.
- Switch to the view with the ViewCube.
- Choose theControl Panel tool from the bottom of the
- Pick the second CV from the center (a "U" to indicate the U direction vector, instead of an "x").
- Hold down the key to magnet-snap, and click-drag with the to move the picked CV upward. Move the cursor near the first CV of the same curve, and the picked CV snaps to the same height as that CV.
(If the CV "flies off" to some other point while moving, with + Z (Windows) or ( + Z (Mac), and try again.)
- Tumble the view to Perspective with either the ViewCube or the keyboard navigation shortcut.
The "zebra stripes" appear continuous as they cross the centerline between the surfaces, indicating that tangency has been achieved.
Construction History updates an object when a source object is modified. Moving the second CV to be in line with the initial CV, and perpendicular to the plane of symmetry provides a tangent condition.