A couple of months ago I did a 3D graphics performance comparison of a number of CAD systems. Today I finally got NX 7.5 up and running on my workstation and decided to load the engine model to give it a spin. I tried importing the STEP file of the engine but got an error with a cryptic message saying “Interrupt”. Not sure what went wrong there. Maybe my NX license didn’t come with a STEP importer.
Anyways, I had previously imported the engine model in Solid Edge ST3. So I could simply read the Solid Edge assembly directly into NX. But that didn’t work either because as it turns out NX 7.5 cannot read Solid Edge ST3 files because ST3 was released later. Now since Solid Edge and NX are both based on the Parasolid modeling kernel I thought of exporting a Parasolid file from Solid Edge ST3 and importing it into NX 7.5. And this is where things started to get really scary. This is what the engine looks like in Solid Edge ST3.
And this is what came into NX.
As you can see a bunch of parts are missing (see update below). The thing that scared me the most was that NX didn’t warn me that something had gone wrong. I was told that the operation succeeded.
Looking for other ways to get the engine model into NX I realized that NX reads SolidWorks files, obviously because SolidWorks is also based on Parasolid. There was no point exporting a Parasolid file from SolidWorks because I had just seen how that went with Solid Edge. So I decided to open the SolidWorks assembly directly into NX. I was absolutely horrified to see what came into NX.
So now I was left scratching my head wondering exactly how I was going to get the engine model into NX. With nothing else left to do I decided to give JT a try. Frankly, I didn’t have much hope. I mean, if Parasolid failed, what chance did JT have? Anyways, I loaded the engine model in Solid Edge ST3 and exported a JT file. Note that by default Solid Edge writes JT files without the NURBS geometry. You need to specifically go to JT’s export options and check the “Include precise geometry” box. Otherwise you will end up with visualization mesh model.
I imported the JT file into NX and to my relief it worked. I did a quick check to see if all the parts had come in and everything seemed fine to me. So in this case Parasolid was not the best way to exchange data between two Parasolid based applications. I am hoping this is just a one off case and not a regular occurrence. If you have faced similar problems please leave a comment with your preferred solution for the benefit of other readers.
So now that I got the engine model into NX 7.5 I gave it a spin. As expected the graphics performance is great. After all NX is a high end CAD system and it has 3D graphics performance worthy of one.
Regarding the missing parts via the Parasolid route, a couple of readers suggested that Solid Edge may have not written the missing parts to the Parasolid file to begin with. They asked me to turn on “Export sheets (constructions)” in the Parasolid export options. They were right. By default Solid Edge does not write out surface bodies to a Parasolid file. Not sure if this default setting is really helpful, but that’s the way it is. My fault for not noticing it. So I turned “Export sheets (constructions)“, wrote out a Parasolid file and opened it in NX. Some more parts came in but there were still parts missing. When setting the Parasolid export options in Solid Edge I noticed there was another option called “Export solids (constructions)“. I decided to check that as well. After doing that all parts came through just fine.