Creating A Helix In Animation:Master
by Jeff Paries

Many people outside of the Animation:Master community as well as those with little experience in the software think it's necessary to jump through hoops to make a complex organic shape, such as a double helix. The fact of the matter is that this is simply not true. In preparing to write this tutorial, a first practice build took all of 3 minutes from start to finish.

For this tutorial, the Grid units were set to cm, and the Grid Spacing was set to 15cm. In addition the Paste/Extrude Offsets were set to 0.

MODELING A "LADDER" SHAPE

The basis of a double helix is a ladder shape.

Begin by creating a single spline that is 300cm long with 11 control points on it. Press Ctrl+A to select the entire spline, and snap it to the grid one unit to the right of the Green Y Axis marker. Figure 1 shows this spline.


Figure 1

Select any point along this spline and click the Lathe icon.

Press Ctrl+A to select all, then enter 25 into the X Scale field, and 35 into the Z Scale field. This will flatten the cylinder shape somewhat.

Drag the selected group to the right (hold down the "1" key across the top of the keyboard to limit movement to the X axis) until it is lined up with the third grid line to the right of the green Y Axis marker.

Press Ctrl+C to copy and Ctrl+V to paste. Drag the newly pasted copy to the left of the Y Axis marker until it is lined up with the third grid line.

Group the top two cross sections of the cylinder on the right and press Ctrl+C to copy and Ctrl+V to paste. Enter 90 into the Z Rotate field on the Properties Panel, and 145 into the X Scale field to scale the newly pasted group between the two vertical cylinders. Align this group up with the first cross section of the two cylinders, as shown in figure 2.


Figure 2

Copy and paste the horizontal cross section that was just created several times, dragging each into position with the appropriate cross section of the vertical cylinders.

Figure 3 shows the model after doing this.


Figure 3

There are two different paths that can now be followed to complete the model. The first is to group sections of the "ladder" shape and rotate them along the Y axis to twist the model up. This works just as well as the second option, but will result in a static model. By using Bones and a Pose to twist the model, it can be animated twisting, if necessary.

ADDING BONES

Continue by clicking the Bones mode button.

Click the Add Bone button and add a bone from the bottom of the model to between the first and second rung of the ladder shape.

Continue adding bones up the model in this manner until you get to the top of the model. This example uses 9 bones.

For the helix shape to twist correctly, it is neccesary to align the bones perfectly along the X and Z axes. This is very important. If the bones are not aligned correctly, the model will bend undesireably while it is twisted. Begin aligning bones in the model by clicking the first bone to select it. On the Position tab of the Properties Panel, enter 0 into the X and Z Start and End positions. With this bone still selected, group the bottom cross section of the model to assign those points of the model to the bone.

Click each of the remaining bones and repeat the zeroing and grouping procedure. Be sure to group the appropriate points for each bone. Figure 4 shows the model after this step.


Figure 4

DO THE TWIST

The final step in creating the helix is to twist the model into shape.

Right click the model name in the Objects section of the Project Workspace and select New, Pose.

Select the second bone in the model by clicking on it. On the Rotate tab of the Properties Panel, change the Edit Angle As type to Euler. Enter 60 into the Z Rotate field.

Select the next bone and repeat the process.

Continue selecting and rotating the bones in the model until you've reached the top. Each bone can be rotated just 60 degrees, since each will inherit the rotation from the parent bone.The completed model looks similar to figure 5.


Figure 5

Click here to see a mpeg movie of the helix
The final rendered helix - click the image to see an mpeg animation


IN CLOSING

It is unfortunate that those with little or no experience in Animation:Master find it necessary to bellow their ignorance on the internet with comments that will surely convince others to avoid the software. As was stated previously, the entire hoopless process of creating this model took less than five minutes. By spending another fifteen minutes or so on it, the model could have been made much more detailed, with sliders to animate the ladder closing up (like a zipper), the helix twisting into shape, and perhaps an action of it dancing onto the screen as a DNA narration is read.

Until next time.....

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


The Animation:Master Handbook
by Jeff Paries