Lamina Design

Lamina Design > Reference > Lamina 1.0 user guide

Table of contents

Overall process

The typical workflow for using Lamina is as follows:

  • Step 1: Export your model from your modeling program. Lamina can read several popular model file formats. Below, we give instructions for preparing your models for use with Lamina in various modeling programs.

  • Step 2: Design and refine cut paths in Lamina. In this step, you use Lamina to design a set of 2-D flat shapes suitable for building your model out of your specified material. During this process, Lamina gives you instant feedback on the accuracy of the design, material requirements, etc. You can refine the design using tools in Lamina, or in some cases, by returning to Step 1 and making small changes in the model.

  • Step 3: Output final design. When you are satisfied with the design, use Lamina to generate:
    • a DXF file of the 2-D shapes, suitable for use with fabrication machinery such as a plotter, waterjet cutter, or laser cutter, and
    • a detailed PDF document with assembly instructions and 3-D views of the assembled model.
    You then use this data to manufacture your model.

Step 1: Export your model from your modeling program

Shapes Lamina can handle

Lamina can help you fabricate a wide variety of geometric shapes, including open, sheet-like surfaces and closed surfaces that surround arbitrary 3-D volumes. Surfaces can have any number of holes and handles. For example, you can use Lamina to build complex sculptures, curved ducting, a boat hull, a wing surface, a custom-shaped storage tank, lettering extruded and distorted in some elaborate 3-D fashion, or even an item of furniture, kitchenware, or clothing.

However, there are a few rules which you must follow. In general,

  • Your shape must not be self-intersecting. That is, no surface of your shape is allowed to pierce any other surface of your shape.

  • At most two surfaces may meet along any given edge of your shape. For example, if you design a cube with 6 square faces, that is fine, but if you try to add some internal structure to the cube such as a diagonal baffle inside the cube, Lamina will not be able to handle the shape.

  • Before you export a file from your modeling program, you must convert all higher-order geometry (such as NURBS surfaces) into polygon meshes. Later in this section, we will provide some guidance on doing this in common modeling programs.

  • Your 3-D model must have correct (outward-facing) normals, it must have correct (counter-clockwise, right-hand-rule-out) polygon vertex order, and adjacent polygons must meet in a water-tight fashion with no cracks or edge vertices that belong to only one polygon. If you follow the advice we give for exporting your data from common modeling programs in this section, your data should meet these requirements with no problem.

Throughout this document, we will point out various tools and tricks in Lamina which you can use to detect geometric problems with your original model. In some cases, you can correct model problems directly inside Lamina, but in other cases you will need to return to your modeling program to correct problems.

If you would like a detailed, technical description of Lamina's exact requirements on the input file geometry, please consult this document.

Supported file formats

Lamina can read input files in these formats:

  • Stereolithography .stl format
  • Wavefront .obj format
  • Rhino3D .3dm format
  • 3D Studio Max .3ds format
In the rest of this section, we will provide guidance on preparing and exporting suitable files from common modeling programs.

A note about units: the modeling file formats above store numerical measurements (e.g., positions and distances) but in general they do not specify the real-world units of those measurements (e.g., inches or centimeters). When you open your modeling file in Lamina, you will have the opportunity to tell Lamina to interpret the numbers in the file as either inches, feet, millimeters, centimeters, or meters. Keep that in mind as you design your model.


If you are using Rhino3D, you will need to convert your NURBS surfaces to polygon meshes and save the file in Rhino .3dm format. First, join all the surfaces of your NURBS object together and join any naked edges. Next, select this polysurface and use the menu "Tools...Polygon Mesh...From NURBS Object" to create a polygon mesh. Finally, save the entire file as a Rhino .3dm file. Lamina will read the polygon meshes from the file and ignore the NURBS surfaces and any other geometry. Dividing lines between NURBS patches will appear in Lamina.

Keeping divisions between NURBS patches in .3dm files

If you want keep the dividing lines between your NURBS patches and have these all available in Lamina, you need to use this sequence to save a .3dm file from Rhino3D.

1. Join all the surfaces of your NURBS object together and join any naked edges.

2. Select the object and use the menu "Tools > Polygon Mesh > From NURBS Object". Make sure "jagged seams" is NOT checked.

3. Move the NURBS object away and select the Polygon Mesh.

4. Click "Explode" to separate the meshes.

5. Save the file in .3dm format.

NURBS modeller

If you are using another NURBS modelling program, join all the surfaces of your NURBS object together before converting the model to a polygon mesh and save the model in Wavefront .obj format.

Other modeling programs

For other modeling programs, export your model in .3dm, .obj, .3ds or .stl format. Rhino .3dm, Wavefront .obj or 3D Studio Max .3ds are preferred, but Sterolithography .stl files will also work.

Step 2: Design and refine cut paths in Lamina

In this step, you use Lamina to design and refine a set of 2-D flat shapes suitable for building your model out of your specified material.

Start Lamina

The best way to start Lamina is to drag and drop one or more icons representing input models on to the Lamina icon on the Desktop. For example, in the Lamina program directory, you can find a Sample Objects directory. Select all of the icons in that directory and drag and drop them onto Lamina's icon on the desktop.

Lamina uses eight modes. The mode can be changed by clicking on one of the tabs on the top of the window.

Lamina opens up in "Browse" mode:

"Browse" mode shows you each model that you dragged onto the Lamina icon when you launched the program. You can click on any given model to work on it.

You can also launch Lamina (specifically, lamina.exe from the Lamina program directory) from the command line or a batch file. Provide the names of one or more input files on the command line. These objects then appear in Lamina's Browse tab.

You can also launch Lamina without drag-and-drop (e.g. from the Start Menu or Desktop icon) and then use the traditional "File...Open File..." mechanism to open your model file. In this case, the Browse tab will remain empty while the program is running.

Set units

Next, tell Lamina how to interpret the measurement units of your input file, and what measurement units you would like to use during the design and output steps, by clicking on the "Edit" menu and selecting either "Inches", "Feet", "Millimeters", "Centimeters," or "Meters."

View your original model

Now switch to "View" mode. You can do this by single-clicking on an object while in "Browse" mode, or by opening a new object with "File...Open." Or, if an object is already open, you can simply click on the "View" tab.

You will see your object in three dimensions. You can examine your object using these buttons:

Click this button and then click and drag over your object to rotate it.
Click this button and then click and drag over your object to translate it left/right or up/down.
Click this button and then click and drag over your object to zoom in and out. The actual size of the object in your selected measurement units (e.g. inches, centimeters) is not changed.

Notice how Lamina has automatically divided your object into sections along any line where there is a sharp edge. The sections are separated by colored cut lines. Each section will become one piece of flat 2-D material—one part—in your final design.

Cut lines can have one of these colors:

  • A red cut line is a sharp edge from your original model where two surfaces meet. These lines are perfectly normal.

  • A blue cut line appears in places where one surface ends and does not meet any other surfaces. If your original model is a flat, open surface such as a wavy sheet, you would expect to see blue cut lines around its edge. If you see any blue cut lines at points on the interior of your surfaces that are supposed to be continuous, this is a warning sign that there is something wrong with your model. Return to your modeling program and look for tiny cracks on that surface, or patches, polygons, or triangles whose normal points in the wrong direction.

  • A green cut line is one that you have added manually yourself inside Lamina using Lamina's "Draw" mode. We will cover this in a later section.

  • A black cut line indicates a serious error with your model. Black cut lines appear in places where more than two surfaces meet along the same edge of your model, which are not allowed (as we explained above). When Lamina displays a black cut line, it will annotate one end of that cut line with three orthogonal black lines to make it easier for you to find the problematic cut line. If a model contains any black cut lines, Lamina cannot process it at all. Lamina will notify you of this with a pop-up window saying "input model is not a shell" when you first enter "View" mode, and you will not be able to enter subsequent modes of Lamina such as "Shape" mode. You need to return to your modeling program and fix the problem with the original model.

At the bottom of the window, Lamina tells you the overall size of the object in terms of the size of the smallest (axis-aligned) box that can contain the object:

You can modify the size of your object by small increments by clicking the up and down buttons. This is different from the zoom function above in that it actually does modify the object and so will reduce or enlarge the 2-D shapes ultimately produced. If you need finer control of object resizing, return to your modeling program and scale the model before exporting it to Lamina.

Flip surface if necessary

If your object looks pitch-black from most angles as you are spinning it around in "View" mode, chances are you need to flip the surface. Here is an example:

To fix this problem, select "Edit...Flip Surface."

What is going on here? Some modeling programs may produce models whose normals point the opposite direction that Lamina expects. This operation flips surface normals to the expected (right-hand-rule, counter-clockwise vertex order) direction.

If only some of the surfaces of your model look pitch-black, and "Edit...Flip Surface" simply exchanges the set of surfaces that look good with those that look bad, then you have a bigger problem: your original model has incorrect normals on only some of its surfaces. You will need to return to your modeling program to correct the problem.

Delete partial lines if necessary

Depending on your model and your modeling program, it is possible that when you examine your model in "View" mode, there may be a few extra red cut lines which are connected only at one end. For example:

These partial lines sometimes appear in areas of your original source model which contain some geometric inconsistency, such as a crease or other sudden discontinuity in the surface normals.

In most cases, these lines will reduce the quality of your 2-D cut shapes and your final results. If you see these partial lines, eliminate them easily and automatically by selecting "Edit...Delete partial lines." Or, eliminate them one by one using the delete tool of lamina's "Draw" mode, which we will describe below.

Set material and join properties

Now, tell lamina about the 2-D flat material you intend to use and how you intend to join your sheets of material together:

Cut loops and floating holes

Before you can generate your first prospective 2-D design with Lamina, you need to make sure your model can be physically built by 2-D shapes. In particular, you need to perform these two tasks:

  • Cut cylinders and other infinite loops: If your model includes a cylinder or other infinite loop, that cylinder must be cut somewhere around the loop in order to be buildable using flat material. For example, this image shows a cylinder which is cut and another which is not cut:

    If you attempt to make a design using uncut infinite loops, you will see strange drawing artifacts such as this in Lamina's other modes:

    This is an indication that you need to cut your model.

  • Cut floating holes: Similarly, if you have a hole in the middle of your material like this, you must add at least one division line between the hole and the outer perimeter of the surface:

    If you do not do this, you will see similar strange drawing artifacts in Lamina's other modes.

So, how can you make the cuts described above? There are two ways:

  • Make the cuts in your modeling program: This method gives you the most control. Return to your modeling program and split NURBS surfaces to precisely define the divisions between parts. When the NUBRS are converted to meshes and saved, Lamina will use the newly created division lines.
  • Make the cuts in Lamina's "Draw" mode: This method is quick and works for simple cuts. Click on the "Draw" tab to switch to Lamina's "Draw" mode:

    You now have several new tools available:

    Using the pencil tool, you can draw new cut lines directly onto the model in 3-D. The cut lines that you draw yourself appear in green. The pencil tool will snap to existing cut lines (of any color) to help you make simple cuts across your existing sections.
    The delete tool deletes cut lines of any color.
    The undo tool is visible if you have made any changes. It allows you to undo multiple previous pencil or delete tool actions.

    So, you can use the pencil tool of Lamina's "Draw" mode to add a cut line along the side of a cylinder or floating hole, as shown in the cylinder on the left:

What should the cut lines look like? Should they be straight or meandering? Should they touch other lines at both ends or only one? Stay tuned: we will answer these questions in a later section of this document.

Generate your first design!

Now, you are ready to generate your first design!

Click on the "Shape" tab:

When you enter "Shape" mode, Lamina computes a complete design for your model, using the sections, material, and flexibility you specified, and it shows you the final 3-D shape as it will appear when you build it from the flat 2-D parts that Lamina has designed.

The shape that you see in "Shape" or "Map" mode might differ somewhat from the original model that you see in "View" or "Draw" mode. In a later section we will explain this important difference, and what you can do to refine your model so that the resulting shape more accurately reflects the original.

But right now, let's satisfy our desire for instant gratification by looking at the complete design that Lamina has made for us!

Click on the "Cut Path" tab:

You will see the complete set of flat 2-D parts needed to fabricate your design. There is one 2-D part for each section of the original model (each region outlined by colored cut lines in the 3-D views). Lamina provides the dimensions of the parts as laid out in the window (to give you a general sense of the size of all parts) and also the dimensions of the largest part.

Click on the "Parts" tab:

Here you can get detailed information about each part. To see a different part, click on it in the row of parts along the bottom of the window.

Lamina provides the size of that part along with a list of numbers indicating what other parts connect to the current part.

If there is some problem with the part, a red dot will appear underneath that part in the row along the bottom of the window. There are several possible errors:

  • "Error: Too big" If the part is too big to fit on one sheet of material at the current sheet size, a red rectangle will appear representing the size of a sheet relative to the part. It is your job to cut the part into two or more parts that will each fit on a sheet, using one of the cutting techniques we learned above.

  • "Warning: Possible self intersection" Some 3-D shapes simply cannot be represented by one 2-D flat part because the 2-D cut out shape would have to have more than one layer of material (that is, the shape intersects itself). Lamina indicates this to you, and it is your job to cut that part into two or more parts so that the self-intersecting regions belong to different parts. Use one of the cutting techniques we learned above.

    Note that sometimes a "self intersecting" error is generated because there is a partial cut line (a line that is connected to other cut lines only at one end). You might try to delete the offending cut line with the delete tool of Lamina's "Draw" mode, or even Edit...Delete partial lines

  • "Warning: Bad fold" If the orientation of the approximated surface differs by too much from the original geometry, this error is created. The most common reason for this is you haven't created a division line connecting a hole in a surface to its outer boundry.

What if you would like to locate a given part on the 3-D model? That is the purpose of "Map" mode. Click on the "Map" tag:

As you rotate the 3-D model, each visible section is labeled with its part number.

This is useful when you are trying to track down problems with parts which you found in "Parts" mode, and it's also useful to help you build the model in the real world!

Finally, Lamina generates a variety of useful general information about the design and the current program settings in the "Info" tab:

Lamina provides the dimensions, area, weight, solid weight, and volume of the structure. Lamina provides the total cut length and join length to help estimate cutting and welding costs.

Add cut lines to increase accuracy

Remember that when you are in "View" or "Draw" mode, Lamina shows you your original 3-D model imported from your modeling program. But when you are in "Shape" or "Map" mode, Lamina shows you how your model will look in 3-D when built from the flat 2-D parts that Lamina has designed.

These two might not be the same: Lamina computes the best possible approximation of your original model, using only the sections that you have defined (that is, the regions outlined by the colored cut lines). Each of these sections becomes exactly one flat 2-D part in the final design. Lamina never adds or removes sections by itself.

So, your goal now is to determine if the approximation is good enough, and if not, add additional cut lines in appropriate areas so that Lamina can do a better job of matching the original model.

Lamina has several tools and tricks to help you determine where the model is accurate and where it is not:

  • When in "Shape" mode, if you hold down the mouse button for a few seconds, the display will alternate between Lamina's approximation and the original model. By rotating the model in different ways and then using this feature, you can see the model "bulge out or in" in places where the approximation doesn't match the original.

  • When in "Shape" mode, you can check the box labeled Show deviation along the menu at the top of the window. Lamina will annotate the model by adding black dots in places where the approximation differs from the original model. The bigger the black dot, the larger the error:

Don't be surprised if you see no bulging and no black dots at all. Lamina may have already found a perfect representation for your model! For example, 3-D models generated solely through extrusion of a 2-D shape can be modeled exactly with flat 2-D parts.

In general, the areas of your original model with the highest absolute Gaussian curvature will generate the most deviation in Lamina's design, and require the most additional cut lines. In layman's terms, these are the areas where you would have to "squish" or "stretch" a flat 2-D sheet of material to make it conform to the shape of the model. Since our construction materials are not like rubber, they cannot squish or stretch, so we have to help out Lamina by allowing more seams between pieces of material in these areas. In general, a flat plane, the side of a cylinder or cone, a piece of corrugated material, or any surface extruded from a 2-D curve will have zero Gaussian curvature. A cup, bulge, sphere, or saddle shape, however, has some absolute Gaussian curvature.

You can even ask Lamina to show you the areas of high absolute Gaussian curvature. In "View" and "Draw" modes, you can check "Edit...Show Curvature" to see a graphical depiction of the Gaussian curvature at various points of your original model. When checked, "Edit...Show curvature" annotates the original model with colored squares in areas of high absolute Gaussian curvature. You will see blue squares for saddles, green squares for concave areas ("innies"), and red squares for convex areas ("outies"). The higher the absolute Gaussian curvature, the larger the square. This may be of use for some users, although for most users the "Show deviation" feature is much more directly useful because it tells you about the current quality of the generated approximation instead of a fixed property of your original model.

In "Shape" and "Map" modes, you can check the box labeled "Show polygons" at the top of the window to get a sense of where and how much you will need to bend the material to assemble the design. In places where the edges of polygons are closely spaced, there is usually a smaller radius of curvature and you will have to bend the material more. The edges of the polygons (the light grey lines) also show you the line along which you will have to bend your material.

Keep in mind the flexibility setting which we described above. This setting allows you to control the tradeoff between the accuracy of Lamina's approximation and the ease of constructing your design. If you find that Lamina specifies excessive bending, try making a stiffer setting. On the other hand, if you find that your material can easily be bent more than the Lamina design specifies, try a more flexible setting in Lamina to see if you can get better accuracy.

What should cut lines look like?

So, you have determined that you need to add a cut line to your model. As we explained above, you can either add cut lines in your original modeling program or you can add them in Lamina's "Draw" mode.

But what should the cut lines look like? Surprisingly, it turns out that almost any shape of cut line which touches other cut lines at both ends is helpful! You can draw a straight line across the desired area, or an arbitrary meandering line that wanders back and forth before reaching the other side of the desired area:

In general, the meandering line will give you a more accurate result than the straight line. That is, if you draw a meandering line, Lamina can generally make you a design that matches your original 3-D model better. But the meandering and straight lines will both help to increase the accuracy of your result. Depending on your particular material and machinery, you may choose the straight line because it is easier to cut or attach, or you may choose the meandering line because it's just as easy either way and you'd like additional accuracy.

Sometimes, it is even useful to make a partial cut line—a cut line which touches another cut line only at one end. Yes, these are the same lines that we were so careful to delete from the original model above! Say there is a large area of your model that is currently represented by one section, and thus one part. Say that area is concave (an "innie") or convex (an "outie") and it is an area where you need more accuracy. By making one or more partial cut lines in this area, you can greatly increase the accuracy of the model in this area without adding more parts. Here is an example:

You can get just as much additional accuracy by making one or more cuts all the way across this area instead of partial cuts. But these full cuts will cause Lamina to generate additional parts:

If it is important to you to keep the part count down, then choose the partial cuts instead.

Never use a partial cut line on a flat area or in a saddle-shaped area, as this will generate parts with unnecessary cuts, "self-intersecting" errors, or other more serious problems.

Also never use a partial cut line when you are also using the "Interlock" (interlock4 type in settings.txt), "Ties" (ties3), or "Hole Tabs" (holetab5) join methods, because the extended tabs of these connection methods will generate self-intersecting parts.

Dangling cut lines, which are not connected to other cut lines at either end, have no effect, and are ignored.

Printing your current Lamina design

You can select "File...Print" and Lamina will create and launch a detailed PDF file showing multiple 3-D views of your object, pictures of each part, and the complete cut paths arranged on material sheets.

You can select "File...Print Simple" and Lamina will create and launch a PDF file containing only the cut paths.

Saving your Lamina project as a .lam file

Any time when you are editing a model, you can select "File...Save Project" to save all of your model geometry, your cut lines, you material properties, and other Lamina settings into a single, standalone .lam file. Once you have a .lam file, you no longer need the original model file. Later, you can drop that .lam file onto Lamina to resume working right where you left off.

Other lamina features

On the "Edit" menu there are a few other features we have not yet described.

"Edit...Clear drawing" clears any modifications to cut lines (of any color) which you've made on the current object.

"Edit...Use shape as input" will copy the current approximation of the source geometry to the source geometry.

"Edit...Show bbox" toggles the display of the light grey bounding box around the object in the 3-D views.

"Edit...Show corners" toggles the display of small points at the endpoints of all cut lines.

"Edit...Show surface" toggles the display of the surface itself. Can be useful for very complex objects.

"Edit...Show balance" toggles the display of marks that show how the object will balance on a planar surface. Corners that the object can be made to balance on are shown in red. Edges that the object will balance on are shown in blue. Stable orientations where three points of support are available are shown in green.

There are a few other settings you can make by using Notepad to modify the settings.txt file in the Lamina program directory. For example, you can affect the size of the digits in the tear-off number tags, the snapping behavior of the pencil tool, or a flatness factor used to simplify the model and the 2-D cutting path. See the file for more details.

Step 3: Output final design

When you are satisfied with the your design, it's time to output that design for fabrication. Select "File...Write Output" and specify the name of a directory. Lamina will create that directory and populate it with the following files:

cut.dxfthe complete set of cutting paths for the project
project.txttextual information about the project
project.lamLamina project file
project.pdffull PDF description of file
shape.objshape of the output model in Wavefront format
parts/partNNNN.dxfDXF cutting path for each part
sheet/sheetNNNN.dxfDXF cutting path for each sheet

Lamina also places a copy of your original model file in the output directory.

Lamina Reference Guide

Here we provide links to explanations of all of Lamina's modes, menu options, and buttons.

Lamina modes
opening new modelsclick for info
examining input modelclick for info
drawing cut linesclick for info
examining approximationclick for info
locating part numbersclick for info
viewing all partsclick for info
viewing individual partsclick for info
viewing project infoclick for info
Lamina menu options
menu optionpurposedocumentation
File...Open file open new model click for info
File...Save project save .lam file click for info
File...Write output save final files for fabrication click for info
File...Print print complete details click for info
File...Print simple print parts only click for info
Edit...Clear drawing clear changes to cut lines click for info
Edit...Delete partial lines delete lines connected at one end click for info
Edit...Flip surface flip normals around click for info
Edit...Use shape as input copy approximation to model click for info
Edit...Show bbox toggle bounding box click for info
Edit...Show corners toggle cut line endpoints click for info
Edit...Show surface toggle surface drawing click for info
Edit...Show balance toggle balance points click for info
Edit...Show curvature toggle Gaussian curvature display click for info
Edit...Add numbers to parts toggle break-off number tabs click for info
Edit...Jitter tab locations toggle uneven tabs click for info
Edit...Inches, etc. set input/output units click for info
Flex menu material stiffness click for info
Join menu material attachment method click for info
Material menu material and thickness click for info
Sheet size menu material sheet size click for info
Lamina buttons
rotate toolclick for info
translate toolclick for info
zoom toolclick for info
resize buttonsclick for info
pencil toolclick for info
delete toolclick for info
undo toolclick for info
show polygonsclick for info
show deviationclick for info

Lamina Design > Reference > Lamina 1.0 user guide