Jack O's in Animation: Master
by Jeff Paries

Well, it's that time of year again, when the little ghosts and goblins start walking the evening in search of a free sugar rush. To help put you in a "Trick or Treat" kind of mood, the following tutorial describes how to create a Jack O' Lantern in Animation:Master '98.

Begin by selecting "New" from the Project drop down menu to create a new project. Right click the Project name and select "Save As" from the available menu. Name the project "Pumpkin" and click OK to save.

The first step is to model the pumpkin shape.

Click for larger image

Click the New button and select Model from the list of available options. Click OK. Create a spline with 11 control points on it shaped similarly to the one shown in figure 1. Press CTRL+A to Select All, and enter 105 into the Magnitude field on the Group tab of the Properties Panel. This will give the spline a nice curvature. From the Tools menu, select Options, and click the Modeling tab. Enter 32 into the Lathe cross sections field. Click OK. Select any point on the spline by clicking it, then click the Lathe button. The rough shape of the body is now done.

The next step is to add ridges to the surface of the model.

Change to a top view by pressing the "5" key on the numeric keypad. Select every other spline, as shown in figure 2 (there are different ways of doing this, do whatever works best for you). It may be necessary to Zoom in to select the correct points. Once the control points have been selected, click the Group tab on the Properties Panel, and enter 98 into the X and Z Scale fields. If you want to make the ridges more pronounced than those in this example, use lower scale values.

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The next section describes how to give the pumpkin a "carved" look.

Zoom in on the top of the model and select the points shown in figure 3. Press CTRL+C then CTRL+V to make a copy of the points and paste them. Drag the copied group upwards away from the main part of the pumpkin. Use the group tool to select all of the points that were just copied on the pumpkin, except those in the lowest cross section (this will leave the spline on the top of the pumpkin and the spline on the bottom of the lid matching). The top of the pumpkin is now open.

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Click any point along the lowest spline of the lid piece and press the "," key to Complement Spline. Click the Extrude button and drag the extrusion downwards past the lowest point of the lid. On the Group tab of the Properties Panel, enter 80 into the X and Z Scale fields. With the group still selected, click the Extrude button once again. On the Group tab of the Properties Panel, enter .1 into the X and Z Scale fields. This will create a surface across the bottom of the lid.

To add realism to the model, peak the points around the edges of the lid. The model should currently look similar to figure 4.

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To match the carved look of the lid along the top of the pumpkin body, click any point along the top most spline of the pumpkin and press the "," key to Complement Spline. This will select the spline that makes up the top of the pumpkin. Click the Extrude button and drag the extrusion downwards into the pumpkin body. On the Group tab of the Properties Panel, enter 80 into the X and Z Scale fields to roughly match the angle of the lid. The lid and the opening in the top of the pumpkin will now match up pretty closely.

The next step is to create the stem.

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Click on any point on the lid of the pumpkin and press the "/" key to Group Connected. Click the Hide button to hide the rest of the model. Zoom in on the model and use the Group tool to select the control points shown in figure 5. Click the Extrude button and drag the extrusion upwards to start forming a stem for the pumpkin. On the Group tab of the Properties Panel, enter 70 into the X and Z Scale fields. With the group still selected, click the Extrude button once again. On the Group tab of the Properties Panel, enter 70 into the X and Z Scale fields. Enter -45 into the Z Rotate field to add some curvature to the stem. Click the Extrude button once again. On the Group tab of the Properties Panel, enter 70 into the X, Y, and Z Scale fields, and -60 into the Z Rotate field. Hold down the Shift key and click the Hide button to hide all of the unselected points. Press the "6" key on the numeric keypad to change to a side view. Press CTRL+A to Select All of the visible points, and click the Extrude button. On the Group tab of the Properties Panel, enter .1 into the X, Y, and Z Scale fields to close the end of the stem. The model can now be unhidden, and the lid can be grouped and lowered into position on the main pumpkin body.

The next step is to "carve" the pumpkin a face.

Begin with the eyes. Create a single spline and shape it however you would like the eye to look. Try to keep the shape such that it will be easy to create a legal surface of 4 point patches (to avoid Boolean rendering artifacts).

Press CTRL+C then CTRL+V to Copy and Paste the first eye. Right click within the selected group and select "Flip, X-Axis" to create the second eye. Drag both of the eye outlines into position. Create a nose and mouth using the same technique. Once the outlines have been created and positioned over the model, they can be rotated to match the curvature of the pumpkins surface. Currently, the model should look similar to figure 6.

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Select the newly created facial feature outlines and name the group "Face". Change to a side view and drag the face group to the front of the pumpkin model. Click the Hide button to hide the rest of the model. Working from a side view, click the Extrude button and drag the extrusion back along the Z axis. Click the Extrude button a second time and drag the extrusion into the pumpkin body. Close the front and back surfaces of the facial features to form rendering surfaces. Select the "Face" named group in the Project Workspace and press the "/" key to add the points extruded from the original group to the named group.

Change to a front view. With the model unhidden, click any point on the body of the pumpkin. Press CTRL+C then CTRL+V to make a copy of the body. On the Group tab of the Properties Panel, enter 95 into the X, Y, and Z Scale fields. With this group still selected, name the group "Guts". This will be the visible inside of the pumpkin.

The next step is to add bones to the model.

While holding down the Shift key, click on one point of each eye, the nose, the mouth, any other facial features you've added, and the "Guts" group. Press the "/" key to Group Connected. The enter face and the inside of the pumpkin should be selected. Click the Hide button to hide the rest of the model and press F6 to enter Bones mode.

From a side view, add a bone somewhere in the model. Use the Group tool to select all of the visible control points. This will assign them to the newly added bone. On the Bone tab of the Properties Panel, place a check in the "Boolean Cutter" checkbox to specify this bone as a cutter. Rename the bone "Cutter" for clarity.

Press F5 to change back to Modeling mode, and click the Hide button to unhide the model. Select any point on the pumpkin body and press the "/" key to Group Connected. Click the Hide button to hide the rest of the model and press the F6 key to change to Bones mode. From a side view, add a bone to the model horizontally, with the bone beginning near the middle of the model and ending near the front. Use the Group tool to select all of the visible points. Name this bone "Body".

Press the F5 key, and hide all but the pumpkin lid. Press the F6 key, and click the "Body" bone. Add a horizontal bone for the lid. Selecting the "Body" bone first causes the "Lid" bone to be added as a child of "body". Group all of the visible control points to associate them with the newly added bone. The main work is done now, and all that is left is texturing.

The main pumpkin was colored using a Gradient material with the following settings:

Start Pos. End Pos. Edge Threshold

0 0 50

0 0

0 0

The First Attribute node:

Diffuse Color: 238, 100, 0 RGB

Falloff: 100

Amb: 20

Specular Color: 255, 255, 255 RGB

Specular Size: 25

Specular Intensity: 100

Roughness Height: 2

Roughness Scale: 70

The Second Attribute node:

Diffuse Color: 255, 128, 0 RGB

Falloff: 100

Amb: 20

Specular Color: 255, 255, 255 RGB

Specular Size: 25

Specular Intensity: 100

Roughness Height: 2

Roughness Scale: 70

The material for the stem is a fBm Turbulence combiner with the following settings:

Translate Scale Amplitude

0 100 100

0 1500

0 100

The First Attribute node:

Diffuse Color: 185, 119, 30 RGB

Falloff: 100

Amb: 20

Specular Color: 255, 255, 255 RGB

Specular Size: 10

Specular Intensity: 100

Roughness Height: 2

Roughness Scale: 70

The Second Attribute node:

Diffuse Color: 128, 64, 0 RGB

Falloff: 100

Amb: 20

Specular Color: 255, 255, 255 RGB

Specular Size: 10

Specular Intensity: 100

Roughness Height: 2

Roughness Scale: 70

The Facial Features were grouped and colored as follows:

Diffuse Color: 255, 196, 136 RGB

Falloff: 100

Amb: 20

Specular Color: 255, 255, 255 RGB

Specular Size: 0

Specular Intensity: 100

Roughness Height: 2

Roughness Scale: 70

The Guts group had a Material applied to it that was just a simple attribute with no settings other than 100% Transparency on the Raytrace tab.

Once the model was placed in a scene, a light that does not cast shadows was added to illuminate the inside of the pumpkin.

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Until next time........

To download the project file for this tutorial, click here

Jeff Paries is employed at Hash and is author of The Animation:Master Handbook.


The Animation:Master Handbook
by Jeff Paries