Getting a new Blissymbol into your tactile symbol set is a multi-step process. There are probably multiple ways to accomplish several of the steps below – these are just the steps that we follow. Some of the steps we go through are the result of complications introduced by Microsoft PowerPoint and others introduced by OpenSCAD. We wish didn’t exist – but they do.
The process, at a high level, looks like this:
- find the Blissymbol you need (in SVG format)
- process the SVG file so that it will be 3D-printable
- convert the processed SVG version into to an STL file
- add the STL file to a tactile symbol
- generate the STL file for the entire tactile symbol
Visually, the process looks like this:
You’ll be following the path on the left and using the “Bliss Graphics STL maker” designer followed by the “Bliss Tactile Symbols” designer.
Where to obtain a Blissymbol?
If you need a symbol to represent a word that’s not part of the core set you’re likely to find the official Blissymbol graphic in the bliss_svg.zip file at Blissymbolics.org. Download and unzip the file. That will create a folder called bliss_svg. The folder contains almost 6000 svg files. Each file contains the svg graphic for a particular Bliss word. One graphic may represent several English words.
| For example, this symbol represents the words “I”, “me”, and “myself”: |  |
Stroke width is too thin
Unfortunately, you can’t directly turn the SVG file into an STL file and use it on a tactile symbol. The lines that make up the graphic are too thin and won’t 3D-print well. Instead, we’ll use Microsoft PowerPoint to “fatten it up”. you should drag and drop the file onto a “new slide” of the “Blissymbol_converter.pptx” PowerPoint file. In the image below we’ve dropped the svg graphic file for the word “animal, beast”:
The image has a bounding box. If you move the image vertically until the top of the bounding box aligns with the top dashed line and the bottom edge of the bounding box aligns with the bottom dashed line, you can see where the Bliss word should sit relative to the skyline (upper solid line) and the earth line (lower solid line):
In this example, the bottom of the symbol rests on the earth line and the top sits halfway between the earth and the sky. Now you’ll use the features of PowerPoint to edit this svg graphic.
Under the “Arrange” menu, choose “Ungroup”. You’ll get a warning:
Click on “Yes”. The bounding box will shrink down to tightly fit the graphic.
Right-click on the graphic and choose “Format shape” from the pop-up menu. Expand the “Line” section under the “Fill & Line” tab. Look for the “Width” property and change the value to “11”. Also, change “Cap Type” and “Join Type” to “Round” if they don’t change automatically. The image will look thicker and the line ends will be rounded:
Note: When you “Ungroup” the image you may get a surprise. Small dots included in the image may disappear. It’s not clear why PowerPoint does this but you can mitigate the problem by first going to slide 1 of the Blissymbol_converter.pptx file and copying the dot that you find there. Go back to your graphic and place the new dot on top of the one in your graphic. Repeat for each dot in the graphic. Now you can ungroup the image and you’ll have dots positioned exactly where they’re needed. If your graphic has a circle, you’ll need to replace it with a similarly sized circle on slide 1. That’s because of the way that OpenSCAD mishandles closed shapes. Once you ungroup the image, delete the circles you see and paste circles from slide 1 in their place.
Now, select all parts of the image and “Group” them.
Right click the grouped image and choose “Save as picture” from the pop-up menu. Navigate to the “SVG files” folder and save your new word in “svg” format with an appropriate name.
This is where things recently got complicated. It appears that Microsoft updated the Office suite and changed the resolution of the SVG files it generates. That means that the version of PowerPoint that you are using will affect the SVG file you generate. In the next step, you’ll need to account for that behavior.
Turn the SVG file into an STL file
There’s a bug in OpenSCAD that causes it to struggle terribly with SVG files created by PowerPoint – turning them into 3D solid shapes and then adding that solid to another solid (i.e., the rest of the tactile symbol). The process takes forever and may then just fail. We’ve worked around this bug by turning the SVG into an STL file and then importing the STL file back into OpenSCAD to create the final tactile symbol.
Launch the “Bliss Graphic STL maker.scad” program. You’ll see a window like this:
Not very interesting yet. Ensure that the “Show Axes” and “Show Scale Markers” options are selected:
Expand the “Graphic Info” section in the Customizer pane:
Type the name of the SVG file that you placed in the “SVG files” folder into the “graphic name” box. Leave the “.svg” off of what you type into the box.
The display will, eventually, update to show your new word displayed on the symbol:
In this case, we’ve added the SVG file for the “and” Blissymbol.
In the image above, the SVG file was created with an earlier version of PowerPoint.
If we repeat the process above with the current version of PowerPoint, the screen will look like this:
This shape is too large…
As you can see from the original SVG file, the symbol for “and” is a relatively small symbol. You can account for the oversized SVG file by choosing “type 2” from the “graphic scale factor” pull-down list. The screen will update to look like this:
This size will now work properly with the Bliss Tactile Symbol designer.
Render the model (Design > Render) and then save it in STL format (File > Export > Export as STL). Save the file to the “beyond core words” folder.
The “Render” step can take several minutes to complete. The more computer RAM you have, the faster the process will go – and vice versa. The OpenSCAD bug is the reason that this can take so long. We hope it will be fixed soon.
If the rendering step fails, either now or when using the Bliss Tactile Symbol designer with this STL, choose “no” from the “chamfered top edge” pull-down list and re-render the graphic. This will create a simpler model which can more easily be rendered and imported into a Bliss Tactile Symbol. Unfortunately, the top edge of the graphic won’t be chamfered and will feel a bit sharper to the touch.
— By the way, if you import your SVG file and it looks like this:
—No problem, just set “graphic scale factor” to “type 1” and you can proceed as normal. Render and export the STL file to your “beyond core words” folder.
Note that you shouldn’t put an apostrophe in the name of this STL file since OpenSCAD won’t be able to incorporate the file into a tactile symbol if it has an apostrophe in its name. Strange, but true…
Create the tactile symbol
Now launch the Bliss Tactile Symbol designer and follow the instructions to create a tactile symbol with your new “beyond core” concept.
Finally, create a new Preset for your symbol to save you time in recreating the design in the future. Create a backup of the “Bliss Tactile Symbol.json” file along with the “beyond core words” folder.
Putting it all together
The following video takes you through the steps outlined above to create an STL version of the Blissymbol that is ready to include in a tactile symbol and then placing it on a symbol: