Importing Black Magic
How to Fix Issues with Your Imported 3D Geometry
Years ago, this is how importing of 3D geometry was once described to me: “black magic”. It was an understandable sentiment as well! Back then, a file was received and it was going to be a gamble whether opening it would be a five minute job or a five day job, fraught with frustration, anger and sadness. Today, we have tools to help ease this pain. The real question now becomes: When and how should I use these tools? Here is a short guide on some of your options.
Enter: Import Diagnostics
Tah-Dah! Our importing savior! Never will you have to clench your jaw and grind your teeth while importing mysterious files from a customer! Well, that is what this tool is advertised as, but in reality it can cause just as much frustration. Don’t get me wrong, the tool is actually pretty nice and does work well. The problem most people run into is it isn’t a cure-all function.
Firstly, the tool should be used immediately upon importing any geometry, even if there are no apparent problems. You will be prompted, upon importing completion, to run the tool or you can right-click on the “imported” feature in the feature manager.
If there is an obvious issue with the import, there will be a red or yellow symbol next to the feature. Regardless of the symbol or lack of symbol, you should still run the diagnostics. Be aware that SOLIDWORKS does allow for certain types of geometry errors to be acceptable. These errors usually will not cause issues. If they do, it isn’t until later in the design cycle and fixing those at this time can cause huge issues to your overall design.
Even if it is a simple part, I still run the diagnostics tool. Also, if any (and I mean ANY) feature has been added to the imported file, the Import Diagnostics tool will not be available anymore. A downside I have run into is with importing assemblies. It would be nice to run the Diagnostics tool at the top level assembly, but this is not an option. Each part must be opened and run individually. It is possible a macro can be utilized here, but be careful! Read on for the reason why...
Once the diagnostics tool is started, DO NOT blindly hit the “Attempt to Heal All” button. Yes, it is a single button click…no, it isn’t a cure-all. In fact, clicking “Attempt to Heal All” may cause even more problems. Take a look at the first box:
The above image is showing how many faces have geometry issues. If there aren’t too many (1-20 issues) then feel free to try the “heal all”. If there are a few more (hundreds to thousands) then feel free to try the “heal all” if you are looking for a break in your day! When the number is that high, there are major issues with the geometry and you should be looking at possibly getting a different data-set from the originating source.
Now, to make matters more complicated, the decision to click “heal all” must be weighed with the second box, which shows how many gaps are in the model.
If there are a large number of gaps, the file may take a long time to “heal” or not “heal” at all! Once again, if there are a large number of gaps you probably need to get a different data-set. If you were given a STEP file, see if you can get a PARASOLID file. If it was a PARASOLID file, see if you can get a STEP or IGES (Yes, I know! Sometimes it works!). In today’s time, we can open most native CAD format files as well, so don’t discount asking for the actual CREO or UG/NX file format.
Well, that didn’t work…
Yes, this does happen. It doesn’t happen as much as it used to, but sometimes we will have to deal with the cards dealt. This might include doing some manual patching after deleting a bad face. Also, this will more than likely include using the surfacing tools in SOLIDWORKS.
Yes, I said it, surfacing tools!
I get many reactions when I say this and they are usually tinted with panic in their voice, “…but I don’t know how to surface!” It’s okay, surface features are no different than solid features. In fact, they are easier to use in these cases! One tool used frequently for patching is the “Filled Surface” feature. The following are the basic steps:
- Delete the bad face which won’t heal correctly with the Diagnostics tool or the Delete Face command.
- Repeat as necessary if there are more bad faces.
- Start the “Filled Surface” command.
- Select all “open” edges – only one hole at a time per feature.
- Once all patches are created, use the “knit” function with all the surfaces selected and have the option “create solid” checked.
- Throw your hands up in success and take the rest of the day off!
(That last step is optional and I will deny ever saying it.)
What it all comes down to is getting a feel for what solution you should use: diagnostics tool, manually fix it, or simply ask the source for a different type of data-set. Hopefully this will help you understand there is no “cure-all” button and it’s not the end of the world if the easy solution doesn’t work. If you deal with importing on a regular basis, I would highly recommend taking the Certified SOLIDWORKS Surfacing course with your local VAR. This class gives step-by-step detailed instruction on what I have explained in this blog. It can also give you more confidence working with Surfaces, which can be FUN!