14 Exercise 4: A Cherry

After having created such a splendid vase, let’s do something a little different. Amapi 3D will help us create a tempting cherry. In this new exercise, we assume that you are now familiar with Amapi 3D. The goal here is to show you that you can, using the tools provided by Amapi 3D, keep your current working habits. We recommend you do this exercise using the shaded display mode. (See chapter User Manual/Edit/Preferences/Interface /Working Space/Display mode.)

Make sure that the scene is empty. Ask to view the entire scene to make sure that it is completely empty. Click on the icon in the Control Panel to do that (or press the “0” key). If the scene is indeed empty, go to the next step. If not, we will erase all the objects using the Catalog’s Trash tool. Þ Click on the Catalog icon to open it . Þ Click on an object of the scene and hold the mouse button down. The Wand is transformed in a thumbnail image representing the object selected. Þ Drag the cursor toward the Trash icon . Þ Release the mouse button when the thumbnail is over the Trash icon. The selected object will disappear from the scene. Þ Repeat the operation until there are no objects left in the scene. Þ Put the Catalog tool aside (depending on the interface).

Creating a sphere, the basis of the body of the cherry.

Select the Sphere tool in the Construction Palette. Two axes that intersect at the center of the table are displayed. Þ As part of the Assistant Palette, Amapi 3D displays in the “Modes” area two buttons used to switch from Polygonal drawing mode to NURBS drawing mode. Click on the NURBS button. (You can also use the keyboard hotkey to switch mode: Ctrl+B on PC, or Command+B on Mac). Þ Set the origin of the sphere at the intersection of the two axes. Þ Drag the mouse so as to define a sphere of radius 120 mm (check the numerical window at the bottom left corner of the scene). Þ Click. The sphere is created. Þ You could smooth the sphere using the “+” and “-” keys. In this example, we will use the default settings. Þ Press the Return key to end the tool action and drop it.

Modifying the sphere shape.
Select the Stretch tool in the Modeling Palette. The sphere created is a NURBS sphere. A NURBS object has a surface that is always smooth even if you modify the object’s shape. Instead of editing the object’s points directly (which is the case for polygonal objects), you will manipulate control vectors external to the shape. Here, the control vectors take the shape of a cube. Þ We can apply a vertical constraint to the cursor’s movements, either through the Assistant Palette or using the hotkey: ¨ In the Assistant Palette: Click on the icon. ¨ Using the hotkey: Press the spacebar twice to set first a horizontal and then a vertical constraint. Þ Click on the center of the top face of the control cube and pull downward by 80 mm. Þ Click to set the point to its new position.

Þ Open the Control Panel and click on the Orthogonal button to set this viewing mode. Þ Switch the Wand to the Lasso. Þ Select the top part of the control cube and press Return to validate: The three top points of the control cube are displayed in red and the cursor switches back to the Stretch tool cursor.

Þ Re-open the Control Panel to go back to perspective view. You can see that you in fact selected the 8 points of the top face of the control cube. Þ Click on one of the points: All the selected points can be moved simultaneously. Þ Drag the mouse upward 60 mm. (You can apply a vertical constraint to the cursor movement by clicking on the icon of the Assistant Palette or by pressing the spacebar twice.) Þ Click to set the points to their new position. Þ Put the tool aside to end the action (depending on the interface). Þ The cube (representing the control vectors) disappears, leaving only the modified sphere.
Hiding the body of the cherry (to have more working space for creating the cherry stalk).
Select the Hide tool in the Control Panel. Þ Click on the cherry (it becomes white). Þ Put the tool aside to end the action (depending on the interface). The cherry disappears in the hidden scene. We will bring it back later.
Building the stalk.
1. Click on the icon in the Control Panel to view the entire scene, or use the hotkey (the “0” key). You will come back to the default viewpoint, as there are no objects in the scene.
2. Select the Drawing tool in the Construction Palette. Two axes are displayed at the center of the table.
3. Select the Polyline tool. Þ Click on the axes origin to set a first point. Þ Click on the icon in the Assistant Palette or press twice on the spacebar to apply a vertical constraint. Þ Move the cursor upward (by about 300 mm) and click to create a second point. Þ Validate to end the tool action. Þ Put the tool aside (depending on the interface).
4. Take the Smooth tool in the Modeling Palette. A red preview of the smoothing is displayed on the object. Þ Press Tab, and enter a value of 8 in the numerical window at the bottom left corner of the screen. Þ Press the Return key to validate. The segment is now divided into 8 parts. Þ Press the Return key to validate. (If you had put the tool aside without validating, the smoothing would not have been applied).
Modifying the end of the stalk.
1. To zoom in on the top of the curve: Click on the icon of the Assistant Palette or use the corresponding hotkey (the “1” key).
2. Take the Drawing tool in the Construction Palette. Þ Set the origin of the axes at the top end point of the straight line. Þ Click at the exact same point. Þ Press the spacebar: The cross displayed indicates a connection point which means that you can continue the drawing using another curve.
3. Select the Polyline tool. Þ Add a few points connecting to the top part of the cherry stalk, as shown on the opposite illustration. Þ Press Return to end the profile. Þ Put the tool aside to end the action (depending on the interface).
4. Click on the icon in the Assistant Palette or use the corresponding hotkey (the “0” key) to view the entire scene. You can see the whole profile of the cherry stalk.
5. Zoom in on the bottom part of the segment: Click on icon in the Assistant Palette or use the corresponding hotkey (the “1” key).
6. Press the Up arrow key a couple of times to display a top perspective view.
7. Select the Drawing tool . Þ Set the axis origin at the bottom end of the segment.
8. Select the Circle from the Drawing tool sub-palette. Þ Click to set the location of the center of the circle. Þ Drag the mouse to specify a radius of 5 mm. Þ Click to validate the location. Þ Press Return to validate the default number of points of the circle. Þ Put the tool aside to end the action (depending on the interface).
9. Select the Snap tool (to attach the end of the stalk). Þ Click on the far right point of the circle; a red dot is displayed. Þ Click on the end of the profile (stalk). The circle snaps to the profile. Þ Put the tool aside to end the action (depending on the interface).
10. Go to front view (the “2” key) and zoom in on the connecting point (click on the icon in the Assistant Palette or use the corresponding hotkey (the “1” key).
11. Select the Extrusion tool in the Construction Palette. Check that the circle is indeed selected (displayed in cyan). Þ Click on the profile. The extrusion is generated and the ends of the stalk are displayed in red. Þ Click on the top one to close the shape. Þ Put the tool aside to end the action (depending on the interface).

Bending the cherry stalk.
Select the Bending tool in the Modeling Palette. Þ Click once to set the axis origin. Þ Click on this origin to create the first point. Þ Click three more times to draw an “S”. Þ Press Return. Þ The “+/-” Tuner is displayed. Press the “+” key to add points to the curve. Þ Validate; the cherry stalk is bent according to the profile of the curve. Þ Put the tool aside to end the action (depending on the interface).
Snapping the cherry to its stalk.
1. Select the Unhide tool in the Control Panel: The hidden scene is displayed (in our case, the body of the cherry). Þ Click on the cherry. Þ Put the tool aside to end the action (depending on the interface). The body of the cherry is displayed in the main scene.
2. Select the cherry stalk: It becomes cyan. 3. Take the Snap tool in the Assembly Palette. Þ Click on the base of the stalk: a red dot is displayed. Þ Click on the point of the cherry as indicated on the opposite illustration. Use the arrow keys to get a better view. Use the “1” key to zoom in on the area if necessary.
Defining the color of the cherry
Þ Amapi 3D assigns a default color to each object. You can render the scene by pressing the Return key. Þ Of course, you can customize those colors. In the Control Panel click on the icon of the Material Editor. A simplified dialog box opens allowing you to assign custom colors to the current object. We will assign a simple red color to the cherry in this exercise. Þ Make sure that the cherry is the current object (it must be displayed in cyan). If not, click on it using the Wand cursor.
Þ Double click on the color rectangle named “Ambient”. The color picker opens up, allowing you to choose a color. Þ Select a red. Þ Click on the “VALID” button to validate the choice. Þ You can check your choice in the preview window, modify it, or make other adjustments. Þ Once satisfied with the color setting, click on the “VALID” button to validate the current object’s new color. The window of the Material Editor closes and you are back to the main scene. Þ Press the Return key to render the whole scene. Þ You can proceed the same way to define the color of the cherry stalk.

Thanks to these tutorials, you have now mastered the basics of Amapi 3D.
You can navigate in space, rotating around the object, zooming in and out, even while using a tool. You have learned to create objects from “scratch” using precisely specified dimensions or intuitively. You have learned that you can modify a whole object or only a part of it. And, finally, you know the principle of toggling and the tools options (constraint along an axis, switching the selection tool from the Wand to the Lasso to the Bullseye, etc.) and the level of undos.
These are the fundamentals of Amapi 3D. If one day you are confronted with a modeling problem, think back to these fundamentals: they will help you find the solution.