Rendering your first parametric DXF file.rst

Tutorial - Rendering your first parametric DXF file

Let’s learn by example.

In this tutorial you will render a parametric DXF file using the :class:`qsketchmetric.renderer.Renderer` module.

We’ll assume you have :ref:`QSketchMetric installed <installation-section>` already.

First download the tutorial.dxf file from the QSketchMetric repository. It is an example of a parametric DXF file that we will use in a tutorial.

To do so, open it and click Ctrl+S to save it to your computer. As a convention, we’ll assume you saved it in a file called tutorial.dxf.

Now, create a new file called render.py and place it in the same directory as tutorial.dxf.

Open render.py in your favorite text editor and import the :class:`qsketchmetric.renderer.Renderer` module as well as the :func:`ezdxf.new` function:

from qsketchmetric.renderer import Renderer
from ezdxf import new
from ezdxf import units

The first one will be used to render the parametric DXF file, the second one to create output :class:`ezdxf.document.Drawing` and the third one to set the units of the output drawing.

Create an output :class:`ezdxf.document.Drawing` object using :func:`ezdxf.filemanagement.new` module. Remember to set the units of the output drawing to millimeters as the parametric DXF file defaults to meters.:

output_dxf = new()
output_dxf.units = units.MM

Before we will render tutorial.dxf let's check it out in the QCAD Professional CAD software to see briefly what it looks like (File -> Open). This is what you should see:

tutorial.dxf opened in QCAD Professional

Note

To see how to parametrize a drawing, see :ref:`parametrization-section`.

We can see it is a parametric drawing of a chalice. To render, it needs variable h that stands for height of the chalice. Let's set it to 50:

input_variables = {'h': 50}

Now we are ready to roll. Let's render the parametric DXF file:

renderer = Renderer('tutorial.dxf', output_dxf, input_variables)
renderer.render()

Finally, save the output drawing:

output_dxf.saveas('rendered_tutorial.dxf')

The whole code should look like this:

from qsketchmetric.renderer import Renderer
from ezdxf import new

output_dxf = new()
input_variables = {'h': 50}
renderer = Renderer('tutorial.dxf', output_dxf, input_variables)
renderer.render()
output_dxf.saveas('rendered_tutorial.dxf')

Now run the code:

python render.py

Finally open rendered_tutorial.dxf in QCAD Professional. This is what you should see:

rendered_tutorial.dxf opened in QCAD Professional

As you can see, the parametric DXF file was rendered successfully and the chalice height is 50.

Congratulation you renderer your first parametric DXF file!