dteal / gdsiistl

Converts GDSII files to STL files.

gdsiistl

Converts GDSII files to STL files.

GDSII files are often large, complex 2D designs for integrated circuits and MEMS chips. 3D visualization of the designs can be very useful, but this is tricky due to the complexity of the files. This is a simple script that extrudes selected layers of the GDSII files into 3D and outputs them as separate 3D STL files for visualization in an external program.

Installation

Install git and Python 3 and its package manager (pip), then install:

pip install numpy
pip install gdspy
pip install numpy-stl
pip install triangle

The modules gdspy and triangle compile C libraries, which may cause trouble on Windows; it might require you to first install Microsoft Visual C++ Build Tools (e.g., from https://visualstudio.microsoft.com/downloads).

Finally:

git clone https://github.com/dteal/gdsiistl

Usage

Suppose you have a GDSII file called file.gds that is to be converted to a 3D STL format.

First, choose GDSII layers to export and their thicknesses by editing gdsiistl.py, specifically, by entering the desired GDSII layer numbers and z bounds in the layerstack variable around line 35.

Second, run python3 gdsiistl.py file.gds. The file will be processed and output files written to file.gds_layername1.stl, file.gds_layername2.stl, etc.

Concretely:

cd gdsiistl
python gdsiistl.py example/example.gds
# output files are example/example.gds_substrate.stl, etc.

Many programs are capable of viewing the output STL files. Blender (https://www.blender.org/) can import STL files, apply materials, and render very impressive visualizations.

Note

Due to a limitation of the library used to triangulate the polygonal boundaries of the GDSII geometry, the polygon borders (i.e., all geometry) are shifted slightly (by a hardcoded delta of about 0.01 units, or 10 nanometers in standard micron units) before export. Furthermore, due to another related limitation/bug (not yet completely understood; see source code comments), extra triangles are sometimes created covering holes in polygons.

So the output mesh is not guaranteed to be watertight, perfectly dimensioned, or retain all polygon holes, but it should be arbitrarily close and err on the side of extra triangles, so a program (e.g., Blender) can edit the mesh by deleting faces and produce a negligibly-far-from perfect visualization.

gdsiistl's Issues

ValueError: [GDSPY] Multiple cells with name <> in GDSII file

Dear Developers,
I recently met a problem when I was dealing with .gds files. I'm using a simulation software called Lumerical, and the gds files they generated could have multiple cells with the same name. Could you please help to think of a way to avoid such problem?
Thank you so much for providing this code. It works fine at situations other than that.

W. Edwards

Easily divided by zero in 45 degrees GDS patterns

Line 153 to 156:
length_ij = np.linalg.norm(normal_ij, axis=1)
length_ik = np.linalg.norm(normal_ik, axis=1)
normal_ij /= np.stack((length_ij, length_ij), axis=1)
normal_ik /= np.stack((length_ik, length_ik), axis=1)
The length_ij and length_ik are easily be zero in offgrid alogn the 45 degrees hypotenuse. Request to add 0.000000001 prevent divided by zero.
length_ij = np.linalg.norm(normal_ij, axis=1)+0.00000001
length_ik = np.linalg.norm(normal_ik, axis=1)+0.00000001
normal_ij /= np.stack((length_ij, length_ij), axis=1)
normal_ik /= np.stack((length_ik, length_ik), axis=1)
To do so, I can easily to translate irregular patterns.

Easily divided by zero in 45 degrees GDS patterns

Line 153 to 156:
length_ij = np.linalg.norm(normal_ij, axis=1)
length_ik = np.linalg.norm(normal_ik, axis=1)
normal_ij /= np.stack((length_ij, length_ij), axis=1)
normal_ik /= np.stack((length_ik, length_ik), axis=1)
The length_ij and length_ik are easily be zero in offgrid alogn the 45 degrees hypotenuse. Request to add 0.000000001 prevent divided by zero.
length_ij = np.linalg.norm(normal_ij, axis=1)+0.00000001
length_ik = np.linalg.norm(normal_ik, axis=1)+0.00000001
normal_ij /= np.stack((length_ij, length_ij), axis=1)
normal_ik /= np.stack((length_ik, length_ik), axis=1)
To do so, I can easily to translate irregular patterns.

Buffer error

Dear all,

The following error message pops up when i try to convert a gds file to stl:

Traceback (most recent call last):
  File "...\gdsiistl\gdsiistl.py", line 52, in <module>
    gdsii.read_gds(gdsii_file_path, units='import')
  File "...\Programs\Python\Python39\lib\site-packages\gdspy\library.py", line 2543, in read_gds
    for record in _record_reader(infile):
  File "...\Programs\Python\Python39\lib\site-packages\gdspy\gdsiiformat.py", line 80, in _record_reader
    struct.unpack(
struct.error: unpack requires a buffer of 616 bytes

I build my gds file in L-Edit, and this could be converted to stl for a while,
however now I get this error and its cause is unknown to me.

The number of bytes changes from time to time.

What could this mean, and how could this be resolved?

kind regards