orthographic drawings vs. 3-dimensional figures

[braillebud]

Please help me understand this. Several lessons in my math book have involved solid figures--3-dimensional renderings of polyhedrons. The tactile graphic images match the print in order to show all the detail. The next lesson (which I've attached) involves cubes and is teaching how to calculate volume and surface area. I'm inclined to continue with the 3-dimensional representation but I'm wondering--should I be following 6.15 in the Guidelines for Tactile Graphics--or, are orthographic drawings a specific concept different from what this lesson is teaching? The front face of my cubes are square, not skewed, so wouldn't the student be able to follow the lesson if these cubes were drawn to match the print in this case? They've just gone through several pages of 3-d rectangles (including cubes). Then again, is it the fact that there are groups of cubes that would require me to follow 6.15? Any guidance would be appreciated!

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[braillebud]

You probably don't have the supplement to Guildeline and Standards for Tactile Graphics, which shows an example of the mat plan. The Winter 2010 edition of the Bulletin also has an article written about these block structures. The skewed angles are very difficult for a blind reader to follow. It's difficult to know whether you are following inside a shape or outside when there are so many lines. Questions #4, 6, and 8 on the lower half of your attachment should really be done using the mat plan. The others could possibly be shown as a "face-on" view, since there are not additional layers behind, but you would need to explain that you are showing a face-on view (i.e. just square blocks, no skewed angles). Question #9 instructs the reader to "make a figure", so they must be working with manipulatives. It is very straightforward for the reader to follow a mat plan and replicate the drawing. I'll attach an example, in case you haven't seen one.
Hope this helps!
Betty
edited by betty.marshall on 9/4/2013

[betty.marshall]

Found the article! Thanks Betty.

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