STL FILE FIXING USING MATERIALISE MAGICS RP (version 18.03).

Several analyst reports expect that the direct market for AM (Additive Manufacturing/3D-Printing) will grow to at least $20 billion by 2020—a figure that represents just a fraction of the entire tooling market today. However, we believe that the overall economic impact created by AM could be much higher, reaching $100 billion to 250 billion by 2025, if adoption across industries continues at today’s rate. Most of that potential will come from the Aerospace and Defense, Automotive, Medical, and Consumer-goods industries.  

As per the present scenario many software's for STL file repairing are available as i have 
discussed in my previous article:

https://additivemanufacturingindia.blogspot.in/2018/04/cad-conversion-and-stl-file-in-additive.html?m=0

In this article I will discuss about STL file repairing with the help of Materialise Magics software and focus upon important fixing operations available in it. Throughout this article I will be using Magics version 18.03 which can be easily accessed and downloaded through Internet.

Materialise Magics RP is a powerful software use to repair 3D files or .STL files for 3D-Printing. Magics bridges the gap between CAD and AM machines by importing nearly all standard CAD formats. I will be using Magics version 18.03 in this study.

Whether you are using Traditional CAD or Other packages such as Google SketchUp, PTC CREO, SolidWorks or Rhino, Magics provides us numerous import options:

1. Manage the resolution of our data while importing (for better STL quality).

2. Import native color information.

3. Fix files automatically during import.

Tip: Working with large files can cause Magics to crash. Save often, and save incrementally so that you can go back to an older version of your file if need be.

Magics Workflow: Use the Fix Wizard tool to repair .STL file before submitting it for 

3D printing. The Fix Wizard tool will guide you through the essential steps to fix a 

corrupt STL file.

1. To bring in your file, go to File > Import Part

2. To start the Fix Wizard, go to Fixing > Fix Wizard

3. Magics will ask about if you want to change the memory state of the part: say Yes.

4. The Fix Wizard should load with the Diagnostics page highlighted. If not, click Diagnostics from the left menu.

5. To run Diagnostics on your file, click Update.

A green check (V) means there are no issues of that kind. Red cross (X) denote specific issues with your file. Your mesh must have green check marks in all fields except Triangles and Overlaps when you submit your file for 3D printing. 

Triangles and Overlaps must be less than 300 each. If your file has all green check marks and less than 300 Overlaps or Triangles, we are ready to Submit.

           

                 

Common .STL file Error types explained.

1. Inverted Normals: In the STL format, a normal indicates the outside of a triangle. When the normal points to the wrong direction (the inside), the triangle needs to be 

    inverted to have a watertight STL. This triangle is then called a flipped triangle.

                       

2. Bad edges: To have a correct STL file, all edges of each triangle should be connected properly to a neighbor. If an edge is not connected properly, the edge is called a bad edge and is indicated with a yellow line.

       

3. Bad contours: A group of bad edges connected to each other form a bad contour.

  a. Near bad edges: Near bad edges are bad edges that are near other bad edges. These are mainly caused by 2 surfaces that are not well connected.

b. Planar hole: A hole consists of missing triangles. Use fill hole to fill it up.

   

4. Intersecting triangles: Intersecting triangles are triangles cutting each other. It can happen sometimes that the STL surface has intersections.

    

5. Overlapping Triangles: An STL-file sometimes has overlapping triangles. These triangles can be removed with the tools in the double surfaces page. 2 triangles are considered as overlapping as: 

       a. The distance between them is smaller than the given tolerance. (E.g. 0,1 mm or 0,005 inch).

b. The angle between the normal of the triangles is smaller than the given angle. (E.g. 5°).

6. Shells: A shell is a collection of triangles connected to each other. Normally a part has only one shell because every triangle of the part is (indirectly) connected to every other triangle.

:

7. Noise shells: Some shells have no geometrical meaning and are considered as noise (waste) that we can throw away. However, it is recommended to look at these shells first before removing them.

STL file fixing in detail.

Diagnostics (Advised way of working):

1. Use the check boxes to indicate what to analyze.

2. The result of the analysis is shown in bold, the V or X indicates if it's ok or not.

3. The features you can analyze. Click on the link for an explanation of what they are.

4. To analyze the checked items.

5. This is the advise, based on the analyzed data.

6. This button will automatically apply the advised fixing operation.

.

Tips and tricks:

Change the advice

You can influence the advice with the check boxes. When unselecting a checkbox, the advice will not take this parameter in account. When Magics keeps on sending you to a certain fixing step, you can skip it this way.

A full analysis is giving you the best result but consider that:

a. Each analysis takes time (especially the overlapping triangles and intersecting triangles)

b. In the beginning you often do not need all information (especially the overlapping triangles and intersecting triangles).

c. Depending for what you're going to use your STL-file afterwards, you may not need to repair intersecting and overlapping triangles.

Combined Fixing (Advised way of working):

Automatic Fixing:

1. Press 

2. Magics will do a set of predefined actions.

3. Go back to the Diagnostics page to see the results, by clicking on

.

Manual Fixing:

Here you can decide yourself what actions you want in the combined fixing.

Fix Normals: Magics will reorient the normal of the triangles automatically. An

STL may not contain any inverted (red) triangles to be watertight (= printable).

Stitching: Two bad edges (yellow lines) which are close enough to each other

can stitched automatically by pulling the open edges towards each other. This

way, you get a watertight STL.

Tolerance: Here you indicate what distance a point may be moved to fix the near bad edge.

Iterations: To get better results, the stitching is done in iterations, starting

with a small tolerance and ending with the given tolerance.

Fill holes:

a. Conditional: Magics will only fill a contour when he recognizes it as a hole. Some contours aren’t holes.

b. Type of hole filling:

Ø Planar: The hole will be filled as it is a planar hole.

Ø Freeform: Complex shaped contours are better filled as free-form holes.

Ø Grid: The triangle size of the surface that is used to fill the contour.

Unify: This will remove all internal geometry and intersecting triangles. This operation will only be done if the geometry allows it.

Filter sharp triangles: Sharp triangles will be removed to improve surface quality.

Click on the Fix button in order to execute the defined manual fixing.

Normal Fixing (Advised way of working):

Automatic Fixing:

1. Press  

2. Magics will do an automatic orientation of the normal.

3. Check if all triangles are oriented correctly.

4. The default color of the inside of a triangle is red. If you still see red triangles, they can be triangles with inverted normal (or a hole).

5. If there are still triangles with inverted normal, orient them correctly with the manual tools.

Manual Fixing:

   

Stitching (Advised way of working):

Automatic Fixing:

1. Press 

2. Magics will estimate a stitching tolerance.

3. Magics will stitch iteratively using this tolerance.

4. Check if there are still near bad edges.

5. Do a manual stitching with a higher tolerance if needed.

Manual Fixing:

a. Tolerance: Magics will reposition points to make triangles of different 

surfaces fit correctly.

b. Iterations: To avoid errors caused by high tolerances, Magics can stitch in iterations, starting with a stitch with a very small tolerance and  ending with the given tolerance.

Noise Shells Fixing (Advised way of working):

Some shells have no geometrical meaning and are considered as noise (waste) that we can throw away.

However, it is recommended to look at these shells first before removing them.

Even a shell of a few triangles can be important.

Automatic Fixing:

1. Press  for automatic removal of detected noise shells.

2. If you're not sure you can remove the noise shells manually.

3. The shells shown in a list sorted by amount of triangles.

4. Use  to select the noise shells.

5. Press  to hide the non-noise shells.

6. If the visible shells do not represent important geometry, you can remove them.

7. Use  to delete them forever.

8. If you're not 100% sure, you can let the selected shells be a different part with the button .

9. It can be that there are other noise shells present. 

Manual Fixing:

Holes Fixing (Advised way of working):

How to recognize a hole?

Automatic Fixing:

1. Press  for an automatic filling of the planar holes.

2. Magics will fill all the planar holes.

a. Non planar holes will not be filled.

b. Planar holes will not be filled if the "new" triangles would intersect existing triangles.

3. Check the part.

4. The new triangles (used to fill the holes) are marked.

5. Check if there are still holes left (non planar holes will not be filled automatically).

6. Use the manual tools to fill the holes that are still left.

7. Use Ruled and Free-form as fill-type for the non-planar holes.

Manual Fixing:

First you’ll need to identify what kind of hole you're dealing with:

   

 

  

 

 

Triangles Fixing (Advised way of working):

Automatic Fixing:

1. Press  for an automatic fixing of triangles.

2. Magics will run some algorithms that will remove untrimmed surfaces and intersections.

3. Because it will give bad results when a bad edge is intersecting a triangle, the automatic algorithm will be aborted.

     

Overlaps Fixing (Advised way of working):

Automatic Fixing:

1. Press  for an automatic fixing of overlaps.

2. Your piece needs to have less than 300 Overlaps for submission in the 3D Printing Center.

3. If you cannot achieve this with Automatic Fixing, you will need to manually fix the errors.

Shells Fixing (Advised way of working):

It can happen that your part consists of multiple shells. Use this tool to manipulate the 

shells. Because this is not really an error, there's no automatic way to solve this 

problem.

Automatic Fixing:

a) Shell list

b) Manual

If the Automatic Fix does not get rid of extra shells or combine your shells into one, you can use the Manual Fix to do these operations. First, you must determine why there are extra shells. Go into the Shells tab in the Fix Wizard, then extend the window down so you can see more of the shells listed.

Click on a shell in the dialog box, and Magics will highlight in green. Click on each individual shell to see which piece of your object it is. You will be able to determine if the individual shells are pieces you need to keep or if they can be deleted. If they can be deleted, select the ones you would like to delete, and click Deleted Selected Shells.

Tip 1: Hold SHIFT and click to select multiple shells for deletion.

Tip 2: Keep an eye on the triangle count of your shells. Shells at the top of the list have many triangles, and these are likely to be the main pieces of our object. Shells with very few triangles, at the bottom of the list, could be extra geometry that we don’t need.

After deleting unnecessary shells, click Update to see if the problem has been fixed. If not, use the Automatic Fix on the Shells page, and Update again. Return to the

Diagnostics page and Update to see the new status of your piece.

Future Prediction for Additive Manufacturing/ 3D-Printing (AM).

The Gartner Hype Curve on Additive Manufacturing/ 3D-Printing.