Lesson Plan Industry Sector
Engineering & Design

## Engineering a Hotter Hot Wheel Part 3- Assembly and Animation

### Lesson Plan Overview / Details

Part 3 of 3 lessons for a Reverse Engineerng/Product Improvement unit.

Students create axles and wheels for their die-cast vehicle using 3D modeling software. They assemble the parts and model a track for the toy. Students then create animation using drive constraints.

Approximately
300 Minutes

### Objectives and Goals

• Students will apply commands and concepts of CAD to model and assemble wheels to their model of a toy car.
• Students will demonstrate using various object-altering techniques by modeling a road and animating their car to "drive" on it.

### Activities in this Lesson

• As students enter the classroom, play the video of the Beatles singing "Baby You Can Drive My Car". Inform students that they will add wheels to their car, model a road, and animate their car so that it "drives" on the road.

• Model Wheels - Demo / Modeling

Students measure diameter and depth of the wheels on their toy car. Instruct students to open a new part file and Sketch a Circle to the appropriate diameter. Finish Sketch and Extrude to measured depth.

To create rims, apply a Sketch Plane to the front surface of the wheel. Use Center-Point Arc and create two arcs with the center of the wheel as the center-point. Connect the two arcs with lines radiating out from the center so as to make a wedge shape a little less than a one-sixth slice of the wheel. Finish Sketch. Extrude cut  and for Extents, choose All. click on Circular Pattern. Use the wedge shape for Profile and the outside curve of the wheel for axis. Choose 6 for number to create six wedge spaces for your rims.

Use Hole to create a hole in the back of the wheel with a .05" diameter. Choose Thru Hole, From Sketch and align to center. For depth distance, use .05" and select the flat drill point.

Click on Work Plane. From the Origin folder, choose the plane that cuts through the circumference of the Wheel. Leave the Visibility on.

Save the Wheel.

• Assemble Wheels - Demo / Modeling

Demonstrate creating  holes for the axles in the toy car model.

Apply a Work Plane to the side of the car. Apply a Sketch Plane to the Work Plane and choose Project Geometry to outline the car profile onto the Sketch Plane. Choose Circle and place one for the front axle and one for the rear axle. Dimension the center points the same distance from the bottom of the car and dimension the diameters to .05". Finish Sketch and Extrude cut, choosing all for Extents.

Recesses slightly larger in diameter than the wheels may need to be cut into the car model for each wheel to fit.

Save the Car.

Open a new Part file and Sketch a Circle. Dimension to .05". Finish Sketch and Extrude to a distance .1" longer than the width of the car (or width of car less depths of recesses). Save the Axle.

Open an Assembly file. Click Place Component and choose the Car. Click Escape to keep from bringing in multiple copies. Click Place Component again and choose Axle, bringing in two of them. Click Constraint and choose Tangent. Click on the front hole in the car and then select one of the Axles. The Axle should fly into the hole. Click Flush, and click on the end of the Axle and the side of the car (or the recessed area). Set the Flush to an Offset of .05". Repeat the procedure for the rear Axle.

Click Place Component and bring in four Wheels. To assemble each Wheel, click on Constraint and choose Insert. Click on the Axle and click on the Wheel.

To constrain the Wheels to each other, Click on constraint and choose Angle. Click on the work Planes from two wheels on the same side of the car. The direction arrows should both point the same way. If they don't, undo the Constraint, rotate one wheel half-way around, and re-do the Constraint. Repeat the Constraint on the other side if the car. Then Constrain the two front Wheels together. Check that all Wheels are constrained to each other by clicking on one Wheel and turning it. The other three Wheels should turn with it. Leave the Visibility of the Work Planes on.

Save this Car Assembly.

• Students model a road or track for their Car Assembly. Note that the road must be wider than the car. Students then Save their Road.

Students open an Assembly File. Place Component to bring in the Road. Click Place Component again and bring in the Car Assembly. Apply a Mate Constraint between the top of the Road and the bottom of the Car, providing enough of an Offset so that the Wheels sit on top of the Road. Use Flush Constraint to align the Car on the Road, clicking on the side of the Road and the side of the Car, providing enough of an Offset to center the Car to the middle of the Road. Apply a Flush Constraint between the back of the Car and the back of the Road.

Apply an Angle Constraint between the back of the Car and the Work Plane of one of the rear Wheels, making sure the angle is set to 0. Expand the Car Assembly in the Browser Panel, then expand the Car Part file. Right click on the Angle Constraint under Car. Click Drive Constraint under Options. Change the End quantity to 3600 and click Play. The Wheels should rotate.

Click Parameters. Find the last Offset, 0 degrees Angular Constraint between rear Wheel and back of Car. Change the Parameter Name to Drive. You can now turn the Visibility of the Work Planes off.

To make the Wheels move, Click Constraint and click on the Motion tab. For Type, select Rotation-Translation. Click on the outer edge of the Wheel, then click on the top of the Road. For distance, enter the circumference of the Wheel; Circumference = 3.14 x diameter.

Right Click on the Angle Constraint under Car. Choose Drive Constraint. Press Play. Your Car should Drive! If it goes backward, change the end length to negative. Adjust other settings in Drive Constraint as preferred.

Save the Assembly.

• In the Drive Constraint dialogue box, click the red button. This records your animation. Press Play to begin recording.

### Assessment

Assessment Types:
Demonstrations,

Students show their media clip of their car's animation to the class.