Continue to Site

Welcome to MCAD Central

Join our MCAD Central community forums, the largest resource for MCAD (Mechanical Computer-Aided Design) professionals, including files, forums, jobs, articles, calendar, and more.

Evalgraph ????


New member
I was try to draw a cam. The tutorial wants you to set a variable sweep and a variing radius realtionship using a function call evalgraph.. does this function work in the 2001 student edition??? has anyone used this function??

thanks dm

also what is

Yes it works in the Student Edition.

1. Use insert>datum>graph this will allow you to sketch a graph in sketcher. Create a sketcher coordinate system and centerlines crossing at the origin. now sketch a function and dimension it as needed. The Y axis values will be used to drive a dimension later.

2. Create you variable section sweep.

3. write a relation for the appropriate dimension like this


This will cause d# to vary according to the sketched graph named graph1.

Trajpar is an internal parameter for Variable Section sweeps which varies from 0 to 1 as the swep progresses along it's trajectory.



Generate CAM Profile using Advanced Variable Section Sweep

Note: Utilize Cut or Protrude to generate the cam profile geometry with VAR SEC SWP.

1. Model cylindrical protrusion in which cam profile will be generated upon. Be sure protrusion diameter is sized correctly for cut or protrusion geometry. If using cut, the initial diameter should exceed 2X the max cam profile radius. If using protrusion, the initial diameter should equal 2X the minimum cam profile radius.

2. Insert Datum Graph, Name the sketch, cam, turn grid ikon on, Sketch, Coordinate system in lower left corner, create center lines thru csys X and Y, sketch lines or spline for the profile starting at Y cl in +X direction, add as many line segments or spline points required for complete cam profile, dimension all points from X and Y csys center lines. Be sure total X dimension of spline equals 360 degree units. Spline starting dimension in the Y direction should equal cam start 0 degrees profile radius. Y dimensions = cam lift. Check Box to complete datum graph sketch. This datum graph sketch will now appear in the model tree and can be redefined at any time to modify the cam profile.

3. Feature, Create, Cut, Advanced, Var Sec Swp, Done, Pivot Dir, select axis of cam, Select outer edge of cylinder 360 or Sketch Traj. Circle on cylinder face. If one sketches the Trajectory, they can create a datum with angle on the fly to control angular relationship of profile to shaft geometry. After sketching Trajectory, the view will auto orient and you will need to sketch the cut in which the variable section will sweep along via the datum graph previously created. Sketch rectangle from cylinder OD to a distance from the axis and add a dimension from the axis. Perform switch dim and record the sd# of the dimension. Sketch, Relations, write relation, sd#=evalgraph(


Articles From 3DCAD World