13 A Vase

In this exercise, we will work directly on the 3D object, moving points and vertices, reshaping the object as a sculptor would.
If you followed the previous exercises closely, by now you should be familiar with the user-interface of Amapi 3D. Therefore, from now on, you will not be given instructions for every single step. We recommend using shaded display mode for this exercise. (See chapter User Manual/Preferences/Work Space/Display mode.)

First, make sure that the scene is empty This time we will use the Trash icon of the Catalog to clear the current scene. · Click on the Catalog icon to open it . · Click on the Trash icon . All of the objects present in the scene disappear. Put the tool aside to end the action (depending on the interface).

Creating a circle, the basis of the shape 1. Go to top view (“5” key). 2. Select the Drawing Palette in the Construction Palette. The sub-tools palette is displayed as well as the reference axes centered on the table. 3. Pick up the Circle tool. · Click to specify the center of the circle and drag the mouse to define a radius of 20 cm. · Click. The “+” and “-” cursor appears to let you edit the number of points of the circle. · Press Tab and enter a value of 12 in the bottom left window. · Press Return to validate this entry. Please note that you can also edit this number of points using the “+” and “-” keys. · Press Return or put the tool aside to end the action and drop the tool.

Modifying the circle to define the cross section of the vase 1. Select specific points of the circle. · Click on the Bullseye icon in the Assistant Palette or, on a PC, click the right mouse button; on a Mac, hold the Option key and click the mouse button. · The Wand switches to the Lasso (for selecting a group of points).

· Repeat the operation. The Lasso is transformed into the Bullseye (for point-by-point selection). Using the Bullseye cursor, select every other point on the circle (the selected points turn red). · Validate the selection with the Return key. 2. Select the Scale tool in the Assembly Palette. Only the points previously selected will be affected. · Click on one of the selected points. · Drag the mouse toward the center of the circle: a white box surrounding the circle follows the cursor’s movements. · Click to end the action. The circle is transformed into a star. · Put the tool aside (depending on the interface). You can see that the tool action is applied only to the selected points. 3. Deselect the points: Using the Wand, click on the star you just created.

Extruding the star 1. Go to top view (“2” key”). 2. Select the Extrusion tool in the Construction Palette. · Click on the star. · Drag the mouse upward and toward the center of the star. · Click: You just created the first segment of the vase. · Create a second segment slightly above the first segment. · Click above the second segment to create the third segment. · Press Return to end the extrusion. · Both extremities are displayed in red, allowing you to cap either or both of them. · Click on the bottom of the vase only. · Put the tool aside to end the action (depending on the interface). If, while building an object, you are not satisfied with your creation, you can always cancel prior construction steps (undo).Ctrl-Z (on PC) or Command-Z (on Mac) will cancel. · Within a tool: the last operation done by that tool. · No tool selected: all of the operations done by the last tool used.

In the first case, there are as many undos possible as there were operations done with the tool. In the second case, the number of possible undos is user-defined in the Preferences menu.

Modifying the top part of the vase 1. Switch to a perspective top view using the up arrow key. Zoom out using the “.” if necessary. 2. Selecting points on the object. (The current object will not be the entire object but only the selected points.) · The Bullseye selection tool can be selected either through the Assistant Palette or using the corresponding hotkey. · In the Assistant Palette: Click on this icon: . The cursor switches into a Bullseye. · Using the hotkey: · On PC: Click the right mouse button; on Mac: Hold the Option and click the mouse button. · The Wand is transformed into a Lasso (tool used to select a group of points). · Repeat the operation: This time, the cursor is transformed into a Bullseye (tool used to select individual points). It is the tool we need here. · Using the Bullseye cursor, select every other point on the top edge of the vase. (They will be displayed in red.) · Press Return to validate the selection. 3. Go back to front view (“2” key). 4. Select the Stretch tool in the Modeling Palette. · We can apply a vertical constraint to the movements of the cursor either through: · The Assistant Palette: Click on the icon . · Using the hotkey: Press spacebar twice, to first set a horizontal constraint, then a vertical one. · Click and drag the selection upward. · Click again to set the selection at the desired location (see opposite illustration). · Put the tool aside to end the tool action (depending on the interface). 5. Using the Wand, click on the vase to deselect the six points. 6. Twisting the vase. We want only part of the object to be affected by this operation, so we need to designate those points before selecting the tool. We will select them using the Lasso. · The Lasso can be selected either through the Assistant Palette or through the corresponding hotkey. · In the Assistant Palette: Click on the icon . The Wand cursor is transformed into a Lasso. · Using the hotkey: On PC: Click the right mouse button; on Mac: Hold the Option key and click the mouse button.

· Surround the points defining the second section of the vase (starting from the top) (see illustration above). · Press the Return key to validate the operation. The selected points appear in red. 7. Go to top view (“5” key). 8. Select the Rotation tool in the Assembly Palette. Centered on the object you will see a circle with tick marks. · Click on the circle at the location where you want to start the rotation. · You can define the rotation increment (as indicated by the ticks on the circle) using the “+” and “-” keys of the numeric keypad. · Drag the cursor in the desired direction for the rotation. The angle value is displayed in the Data Window like any other data. · You can click to validate the angle of rotation, but in this example we will enter the angle value directly. Press the Tab key to edit the Data Window and use the keyboard to enter an angle of 45°. Press the Return key to validate the entry. · End the action (depending on the interface). 9. Go to front view (“2” key). 10. Deselect the selected points. Click on the vase to select the entire vase and thus deselect the points previously selected.

Smoothing the vase Take the Smooth tool in the Modeling Palette. A preview of the smoothing is displayed in red on the object. Amapi 3D can generate additional facets to smooth the object’s surface depending on the smoothing value you specify The number of polygons will be multiplied by the square of the smoothing value (i.e., a smoothing of 3 will multiply the number of polygons by 9). The higher the smoothing value, the smoother the object, but also the bulkier the file. There are different ways to set the value: Clicking on the icon in the Assistant Palette, pressing the “+” and “-” keys of the numeric keypad, or entering the value directly in the Data Window. · Set a smoothing value of 5; a preview of the smoothing is displayed in red on the object. · Click on the vase; the smoothing is applied to the whole object. · Put the tool aside to end the action (depending on the interface). The object appears as it was before, but the smoothing is not lost; it is saved in memory and will be applied only when rendering, so as to not degrade object manipulation performance.

Defining sharp edges You can define points where the smoothing will not be applied – at these points the edges will stay sharp. Reselect the Smooth tool . A red preview of the previously defined smoothing is displayed. Selecting the shape edges: · Go to top view. · Switch the cursor to the Bullseye. · Using the Bullseye, select every other edge of the top part of the vase. · Press the Return key to validate. · Click on the vase to display the smoothing. The selected edges are still sharp while the other are smoothed and rounded. · Press return to keep the smoothed wireframe displayed on-screen. · Complete the action by releasing the tool (depending on the interface).

Rendering the scene Make sure that no tool is selected, then press the Return key to render the scene.