Intelligent Models Made Easy (On the Edge Solid Edge Tutorial)30 Jun, 2007 By: Russell Brook
Adding intelligence with the Auto-constrain command to imported assembly models in Solid Edge.
As more companies operate within global supply chains, the need for design collaboration has never been greater. As well as the usual need to review (view and mark up) projects, companies also need to share their data and open Solid Edge files received from their partners. In many cases, they don't have control over which design system the data was created in.
Solid Edge can read Parasolid, NX and I-deas data directly. To use data from other CAD systems, Solid Edge offers neutral data-exchange translators (STEP, IGES and ACIS) and migration tools that directly read Pro/ENGINEER, Inventor, SolidWorks and other files. Making intelligent use of this data manually is both time consuming and labor intensive. The Auto-constrain command in Solid Edge provides an interactive way to detect and apply assembly constraints to imported data, regardless of where the data originated.
This month, I'll show you how to use Solid Edge's Auto-constrain command to quickly add parametric assembly relationships to imported assembly files. Next month, I'll talk about Direct Editing, which lets you directly modify geometry on imported data or complex Solid Edge models.
Using Auto-constrain in the Real World
After applying Solid Edge's Auto-constrain command to imported and native data, you can use your designs in Solid Edge with intelligent features such as full-motion studies, exploded views or methods to maintain the correct location of your components.
The Solid Edge Auto-constrain feature can add every single constraint to underconstrained 3D assemblies in a single pass, but usually you need more control over the process to ensure you get the correct constraints. To do get this control, Solid Edge provides selection options that help to apply relationships you require.
Let's peek under Auto-constrain's hood to take full advantage of it and then good working practices to help you get the most out of this powerful time- and labor-saving command.
Let's start with imported geometry, in this case a STEP file. As soon as you read the assembly into Solid Edge, you'll notice that all the parts are grounded; that is, they're correctly positioned and locked in place.
Importing STEP files into Solid Edge.
Imported STEP files have all components in position and correct assembly structure. All parts are automatically grounded.
Because we are adding parametric constraints, we must remove the ground relationships to allow Auto-constrain to do its job.
To remove the ground relationships, choose the Auto-constrain command and simply drag a box around all of the components. An option in Auto-constrain automatically removes the default ground relationships on all of the parts before applying new relationships.
It's a good working practice to start with cylindrical alignments and then apply mates and planar alignments. Solid Edge ignores existing relationships as you progress through the process.
In this example, separate those parts that need to move from those that are static by hiding some components.
Now run the Auto-constrain command, but this time chose the option to Check select set one against a Second select set. The first select set is the base of the pneumatic slide. The second select set is all of the remaining parts that you pick next.
When you're satisfied with the select sets, you can move to the next step: defining the types of relationships you want to detect. In this first round, look only for axial alignments.
Here axial alignments are being processed. After you accept the constraints, they're automatically applied between the components.
While still in the Relationship Assistant, you can apply more relationships to the same select set. This time, detect all mates and planer alignments. After clicking Process, Solid Edge searches for any faces that are in close proximity and that touch or are on the same plane.
Finally, you will detect planer alignments and allow an offset. If there are any relationships you don't want to apply, simply uncheck before clicking Accept.
To continue constraining the assembly, you can show all the components you hid earlier. Next, you'll go through the same process to build the assembly relationships between the components on the moveable half of the pneumatic slide. You'll want to detect constraints between the top plate of the slide and the remaining components.
Apply the same Auto-constrain process to the slider assembly and then axial align the two subassemblies.
Finally, detect a relationship between the top and bottom halves of the slide. Simply change the select sets and process the types of relationships you want to detect.
The piston rods are not fully constrained, because we want them to move freely in and out of the slide body to simulate the action of the pneumatic slide.
Use Imported Data Intelligently
Using Solid Edge's Auto-constrain functionality, you can import a mechanical assembly from a supplier that had absolutely no intelligence, and it quickly adds assembly constraints. For anyone working with imported data, this capability saves many mouse clicks and time. It also lets you easily use foreign data in exploded views and drawings in motion studies and more.
This wraps up this month's column, next time I'll continue on our imported data theme with using direct editing.
See you "On the Edge" next month.
About the Author: Russell Brook
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