Exporting a model as IGES (STEP) vs. liveTransfer

Generally models made from scan data that are intended to be edited in a CAD program are transferred into the receiving CAD program using IGES or STEP file format. Even after a successful import of these formats into the CAD modeler there may be some gaps or bad topology condition in surface body.

This technical tip will introduce “Live Transfer” an effective way to use XOR so that you can transfer a design data to the receiving CAD modeler without these problems.

How to transfer data to the other CAD modeler without any problems?

As you might have experienced, the data which is modeled in XOR and exported to the other CAD modeler could have some gaps from bad topology condition of the surface body if you transferred the data using neutral file format such as IGES, STEP as shown in the image below.

It might have happened because each application has its own specific tolerance and healing option. If that’s the case then what is effective way of transferring data to another CAD Modeler? XOR has a transferring system called as live transfer which would solve the problem.

Live transfer has several options. If you use “Start from first feature” option, the application makes a body in the other CAD modeler in the same order of the modeling process as you did in XOR. You will get a modeled body as well as modeling history which is exactly the same as you did in XOR.

If you use “Only Selected Entities” option, the application transfers only the selected body to the other CAD modeler. In this case they use “parasolid” file format which is of higher data compatibility. So you will get better results than what you get when you transfer a modeled data using IGES, STEP file format.

If you have been using XOR and already installed other CAD modeler in your machine, use live transfer to transfer model to the other CAD modeler. You will get better a result as shown in the image below.

Rapidform XOR/XOS can create a body on a mesh using “Auto Surfacing” command. This method can quickly and automatically wrap the mesh and create a surface/solid body with just one click of a button, but it might be possible for gaps to be created between patches on complicated and sharp areas of a mesh. So in such cases if you want to export the created model from XOR/XOS to other CAD system such as CATIA, UGS NX or PRO/E Wildfire, you need to perform additional processes to heal the gaps after transferring to other CAD system.

This technical tip is useful when you export a surface / solid body as neutral format (IGES or STEP) into CATIA to create a complete watertight solid model.

As you see the model tree as shown in the image above, the patches are broken after importing a body into CATIA. If you want to create a complete body, you need to use healing Process in CATIA such as heal and join in Healing Assistant.

Method

This method is used in the Healing Assistant Workbench or Part Design Workbench. If created model has many patches and curves, this model has highly possibility of error occurrence. Therefore it needs to be healed for broken patches.

In Assistant Workbench
1. Click Start > Mechanical Design > Healing Assistant in the menu and click the (Heal) button in the Tool bar. Select all imported surfaces and click OK button as shown in the image below. If CATIA cannot heal some edges, these edges are displayed in green. In that case, increase the tolerance value little by little (max. 0.1) and try to heal again.

Note
The Heal command improves surface connection condition. If adjacent surfaces are completely connected and closed within the given allowable tolerance, then you can skip this stage.

Note
If you skip the above healing process, you can create a combined body by clicking the (Join) button in the tool bar as shown in the image below. Click the OK button.

In Part Design Workbench
1. Click the Start > Mechanical Design > Part Design in the menu and click the (Close Surface) button in the Tool bar and select the joined body in the Model Tree as shown in the image below. Click the OK button.

2. This command transfers the surface body to a solid body and registers it in the model tree. Finally, you will obtain a Closed Solid body.

As an aside, it’s important to know how to properly import and triangulate point clouds from Leica and other long range scanners.  For very large data sets, using the 64 bit version of Rapidform is a good idea, and in XOR and XOS, the Add-Ins menu has some great tools for importing large data sets (helpful on both 32 bit and 64 bit setups).  To triangulate (i.e., make a mesh) point clouds from “spherical” scanners that project out and collect data all around them, use 2D Triangulation and set it to Spherical.