So…. you have a part in your Content Center. It’s a purchased part, and you got a Step file from a supplier, which you authored, and published and tucked away neat and clean. The block was a fairly “dumb” part. The internals are not modeled, and the parts is really nothing more than the “shape” and size of the object in question. No problem, as long as the envelope dimensions are correct, right? But then, someone comes along and says, we need to get the weight of all of these parts to find center of gravity. What do you do to get the correct weight on these Content Center parts?
You could use the primary method of editing geometry or parameters on a CC part. Open from Content Center, select the part and open “As Custom” and save a working copy of it. Make the changes, in this case simply override the weight on the Physical Properties tab of your iproperties. You’ll see the familiar hand symbol indicating that the value was hand entered.
The problem here, which I have run into before, is that a Mass override does not reliably factor into center of gravity. The COG is based on density and mass. So that means you need to change the part’s density in such a way that you end up changing the mass to the known part weight. How? Well, you have the model’s Volume in the image above. Presumably you know the desired weight, perhaps from a catalog. So d=m/v. Divide the known weight by the part volume to arrive at the material density you need for that part. So…. now you can edit the part’s material, or create a custom material if you wish, and set the density from the equation above. With this, your Mass value will update accordingly and should give you the known weight. Be sure to type in the full density value including all decimal places for a hyper accurate weight value. Done?
Not quite. The method is good, the problem is that this doesn’t quite work on Content Center parts. When you opened and saved the copy of the part, it created a new part file with it’s own material settings. Going back to the Content Center and using “Replace Family Template” does not override the actual CC part’s material library settings. Opening the part from the CC “As Standard” doesn’t allow you to make changes to the iproperties and save them. So, now what?
Tag this one under the workaround portion of my blog name. What I did was to create a working folder specifically for Content Center part changes. This working folder must be under your active Inventor Project search paths. Then, from Windows Explorer, I opened two windows. In one I navigated to the Content Center folder where the part file lives. This is the folder under your official CC location. Content Center\en-US etc. This is where Content Center generates all new CC part files the first time you open or place a part from your library. When these are checked into the Vault (if you use Vault) and local copies are deleted, the folder remains but is obviously empty. When you check one out from the Vault, it is downloaded back to this location…. so this is it’s official home. I open the other window to my CC working folder. Then I rip the part from it’s home and move it to the working folder.
From there I can easily open the part in Inventor, change whatever I want and save it with no errors. At this moment, the part is no longer a CC part. Once I’m done editing, I save it, close it and move it back to it’s home folder in the CC path. Mission accomplished.
I’ve had this called, by an Autodesk employee from the Inventor team, a very old school work around. Well, I am fairly old school so I’m ok with that. Doing this, I was able to modify the density on a series of parts and get an accurate weight on my design skid. The nice thing about this editing method is that no “Refresh” of standard components is required. Once the assembly using these parts is reopened, the changes are there. If you DO use Vault, check these in right away, so anyone else using these parts can take advantage of the newly modified data.
There you have it, an old school fix to a simply complex issue.