Computer Aided Design : ~1421/tutorials/animation1/combinecomponents


CAD / Jimmy Figiel / tutorials / animation1 / combinecomponents

Combine Components

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Now we are going to put all of the pieces together that we built in the last section. The key to assembling the pieces is to take note of what pieces move when another piece moves. For example, when the upper arm moves the bucket moves with it. When the lower arm moves, the upper arm and the bucket move with it. I call the end that does not move any other pieces (the bucket) the finger.

Start at the finger and connect the next level to it. In MLCAD, start a new model. Drop the digger bucket and the upper arm into the 3D view. This places them both with their origin (where we have the rotation point) at 0,0,0. Now move the finger (the bucket) to the place where it should connect to the upper arm. I like to have the pieces set up in thier defalt location, so I rotate the bucket around the Z axis until it is tucked right under the upper arm. Make sure that the rotation point setting in MLCAD is set to the part origin. This causes the piece to be rotated around where we put our rotation point.

Now we need to add a comment to the model that will specify that this connection will be articulated and name the connection. Add a comment to the model directly above the part that is going to move. The comment should say

Joint X bucket

This comment specifies that we are creating a bendable joint. The joint is going to bend around the X axis, and will be called bucket.

Make sure that you set the color of all the components to the main-color 16. If you don’t, there may be a problem with the way the sub part colors look in the rederd image.

Save this model as DiggerArticulatedUpperArm. Here is the complete listing of the piece. MLCAD adds the word WRITE in the comment.

0 Digger Articulated Upper Arm 0 Name: DiggerArticulatedUpperArm.ldr 0 Author: Jimmy Figiel 0 Unofficial Model 0 ROTATION CENTER 0 0 0 1 "Custom" 0 ROTATION CONFIG -1 0 1 16 0 0 0 1 0 0 0 1 0 0 0 1 DiggerUpperArm.ldr 0 WRITE Joint X bucket 1 16 0 0 -100 1 0 0 0 -1 0 0 0 -1 DiggerBucket.ldr 0

This combined piece is now the finger for the next piece (the lower arm). Continue attaching all of the pieces until the model is built. The last piece (which I call digger chassis) has more than one finger attached to it. Each wheel is a finger. Since this connection is the last one, I simplified the name of the file to digger. I put a rotation point into digger to specify where the ground was and to specify where the rotation point of the entire model is when it is in a scene. Images of all the pieces are below. The ldraw files are in the ldraw files section below.

Digger Articulated Upper Arm

Digger Articulated Lower Arm

Digger Articulated Cockpit

Digger Articulated Chassis

Digger

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