Beginner needs help

Hi, I 'm from Germany and my English is terrible . But I still try to ask a few questions . I work only a few weeks ago with Rhino and Exactflat . I import a 3D model as a STEP file in Rhino and i use exactflat for flattening.
For each pattern piece I have to run the command pelt for pelt flattening. Then i use the Find function to locate the matching 2D piece to a selected line on another 2D piece, to position the pieces in the work area as they would be assembled. Next, I have to number all edges matching together. Then gets each face two border with different layers. Finally , each area has a name with a sequential number in the name as an example Piece P1 , Piece P2 …The text and the edge numbers must be aligned at the edges.
Now to my questions:
Can I use the Exactflat command pelt in a loop for each piece?
Is there a script that position the pieces in the work area as they would be assembled.
To number all edges matching together, i use Paneling Tools unroll faces and copy matching faces together to get the right edge number. :frowning: At the moment, i can´t use Unroll Face because of a bug that flipped some faces. Is there a script that matching edges numbered?
Can I use the command _offset with options/parameter in a loop for each piece?
Is there a command to aligne Text and Numbers to a edge by click?
Has Exactflat any options or parameters to work in a script?

I am grateful for any help. Notes and links to Scripting Pages are welcome. Please excuse my bad english , I hope you can understand me.


@lukeniwranski, is this something you can help with?

Hi Chris,

The _EFPelt command will stay active until you press the Escape key. You can pelt as many faces as you like. You can also re-pelt the same face as many times as you’d like.

It is also important to know that ExactFlat is a two stage flattener. Commands like _EFPelt, _EFFracture, and _EFConvexCombinationMap are all very fast initial or pre-flatteners. They do not produce a straint/sag free pattern piece. Their job is simply to produce a 2D flat pattern with little to no flipped triangles in the ExactFlat patterning environment. Once you have a 2D pattern, it needs to be optimized using the _EFSpring command. The spring command will allow you to choose a material for pattern optimization and configure the optimizer for things like no seam stretch. The optimizer takes much longer than the pre-flatteners, but it’s job is to minimize the average energy density to as close to zero as possible.

There is no script that will do this automatically. However, you can use the _EFFind tool to automatically translate and rotate an adjoining piece to align with the selected edge.

You can use the _EFNotchTag command to add notching and edge labeling data. The command allows you to add notches and labels to edges by simply selecting the desired location on the edge. Once a notch tag/label has been added to an edge of a piece, the notch will automatically in the correct location on the adjoining piece.

I would recommend doing all flattening and optimization first before using commands like _Offset. They will work on ExactFlat meshes, but ExactFlat will probably overwrite the results the next time you perform an ExactFlat operation.

There are a few alternatives that may work better for you. The best method is to simply export your pattern as a DXF using the _EFExport command. This will automatically add a global seam allowance to all pattern pieces (a value of 0.0 is valid and indicates no seam allowance). All notching, tagging, and tracing data is exported to the DXF. If different seam allowances are required on certain edges, then you can edit the DXF. Alternatively, you can form a planar surface form the piece and use the _Offset command to create your seams.

Another option is to use the _EFFinish command to end the ExactFlat session. You have the option of keeping your flat pattern as either a mesh or a surface. However, notching, tagging, and tracing data is not preserved.

We don’t really have any options or parameters for scripting. You may be able to script some of the basic commands, but most of our commands require some level of higher interaction. For example:

  • The results produced by the _EFFracture command depend entirely on
    the selected starting edge.
  • There may be some cases were optimizing a pattern piece is not
  • The location of darts may depend entirely on the remaining strain on
    the pattern piece after optimizing. Placement of darts then becomes
    a human problem based on the displayed strain map.

If you would like help flattening a specific file then feel free to e-mail us at We would be happy to have a look at your file and give you helpful suggestions to produce the best flat pattern.

We also offer training on best practices with ExactFlat. We cover all topics starting from model preparation, meshing (including FEA mesh generation using our remeshing tools), flattening, tracing, notching, tagging, optimizing, and exporting.

I hope I was able to answer all your questions. Please let me know if there are any other questions I can answer for you.

Hi lukeniwranski,

thank you for this detailed answer. Can you please explain the difference between exactflat and _ptunrollfaces. I have to extract all surfaces from a 3D Inventor Model. The surfaces must be absolutely the same dimensions as in the 3D model. Sometimes , but not often is a double curved surface thereby, but _ptunrollfaces can handle it. I think so but i´m not sure.
I only need closed polylines for surfaces, two boarders around the surface, aligned text and numbers on the edge. :wink:


Hi @Chris_Stoffel_04,

I apologize for not responding sooner. For some reason I didn’t get a notification that you had replied!

I’m not sure how _ptunrollfaces works, so I can’t really describe the differences. However, I can say that ExactFlat will flatten any surface whether it’s planar, developable, or contains double curvature. Organic shapes are not a problem for ExactFlat.

For developable (or near-developable) surfaces, ExactFlat will produce a perfect pattern using only the fracture pre-flattener.

Once you have your flat patterns, you can use the labeling tools to label your edges and faces. Our DXF export command can be used to generate a DXF containing the piece edge, a cut edge (piece edge + seam allowance), notching/tagging information, and any geometry that was traced from the 3D surface to the 2D pattern.

What exactly do you mean by a polyline with two boarders?