Plotting/Printing Blender Files to Scale
Above is a Blender mesh cube, exported as an .obj file, and imported into the free Sweethome 3D program as "furniture". On import you can tell the program the dimensions of your object. To create dimensions you can print (like what you see above) use the "Create dimensions" button which has a very nice dimension snapping tool. You can add any text (as you can see ".OBJ Block Import from Blender" is what I typed into a "Add texts"). Then just output as a "Print to PDF". The above items were cropped from a 3 page output (it creates a material list page, a drawing/sheet page, and a 3D view page in the PDF document.) You can set the output print scale in the "Page setup..." tab on the left "File" pull-down menu (the above is set to "Best fit scale" but you can also set it to Scale to any fraction of 100.)
DEPRECATED METHOD
I previously recommended a method of using the Orthographic camera, setting the rotation to 0 degrees on every axis, creating a "dimension sheet" mesh plane the size of the paper you were going to print it on and adjusting the Orthographic scale until it frames the "dimension sheet", then if assuming a render resolution of 150 DPI, one would multiply the paper dimension (let's say width was 8.5") 8.5 x 150 = 1275 pixels by (length 11")
11 x 150=1650 pixels and make that the render window size (1275 pixels by 1650 pixels), then output the render, HOWEVER, I see in Blender 2.91 that the original Orthographic Scale I recommended previously (0.279) no longer frames the "dimension sheet" perfectly. I do not know why a dimension sheet would not be framed perfectly (as it was previously), and it cannot be framed perfectly in the new version, but I suspect that there has been some minute corruption of the scale in Blender's Orthographic Camera, as I've double checked the metric conversions and it should frame perfectly in Ortho, but it no longer does.
Considering that, one might consider outputting the file anyway (it's very close) but I personally would call it N.T.S. (not to scale). Also one could take the rendered output image and importing it into the free open source Libre Office Draw or Open Office Draw programs, select the sheet size you want, remove the margins in Format Page, then insert the image onto your sheet, dragging the corners if necessary to make it snap perfectly onto your sheet. You could now PDF your drawing and e-mail it to a client, or better yet, do your entire sheet Title Block, Notes and Drawing name in Libre Office/Open office, and then PDF it. Make sure to "Export to PDF", not print to PDF, that way you also have total control over removing compression (which can really mess up the output if you don't) and also making the DPI output the same as what you chose for the image. In Blender 2.79 I e-mailed a test PDF to a different computer, and printed it on a HP laser jet, and when measuring a 1", 1:1 scale test block I put in the original render, it was accurate, but like I said, I see in Blender 2.91 that the Ortho camera appears to be slightly inaccurate.
I believe there are now other ways to plot directly from Blender (perhaps in mechanicalblender or in 2.9?), and when I find them I'll post them here. Another way to derive .pdf's from these models would be to use the free Sweet Home 3D program which has a native easy-to-use .pdf sheet output to scale.
I previously recommended a method of using the Orthographic camera, setting the rotation to 0 degrees on every axis, creating a "dimension sheet" mesh plane the size of the paper you were going to print it on and adjusting the Orthographic scale until it frames the "dimension sheet", then if assuming a render resolution of 150 DPI, one would multiply the paper dimension (let's say width was 8.5") 8.5 x 150 = 1275 pixels by (length 11")
11 x 150=1650 pixels and make that the render window size (1275 pixels by 1650 pixels), then output the render, HOWEVER, I see in Blender 2.91 that the original Orthographic Scale I recommended previously (0.279) no longer frames the "dimension sheet" perfectly. I do not know why a dimension sheet would not be framed perfectly (as it was previously), and it cannot be framed perfectly in the new version, but I suspect that there has been some minute corruption of the scale in Blender's Orthographic Camera, as I've double checked the metric conversions and it should frame perfectly in Ortho, but it no longer does.
Considering that, one might consider outputting the file anyway (it's very close) but I personally would call it N.T.S. (not to scale). Also one could take the rendered output image and importing it into the free open source Libre Office Draw or Open Office Draw programs, select the sheet size you want, remove the margins in Format Page, then insert the image onto your sheet, dragging the corners if necessary to make it snap perfectly onto your sheet. You could now PDF your drawing and e-mail it to a client, or better yet, do your entire sheet Title Block, Notes and Drawing name in Libre Office/Open office, and then PDF it. Make sure to "Export to PDF", not print to PDF, that way you also have total control over removing compression (which can really mess up the output if you don't) and also making the DPI output the same as what you chose for the image. In Blender 2.79 I e-mailed a test PDF to a different computer, and printed it on a HP laser jet, and when measuring a 1", 1:1 scale test block I put in the original render, it was accurate, but like I said, I see in Blender 2.91 that the Ortho camera appears to be slightly inaccurate.
I believe there are now other ways to plot directly from Blender (perhaps in mechanicalblender or in 2.9?), and when I find them I'll post them here. Another way to derive .pdf's from these models would be to use the free Sweet Home 3D program which has a native easy-to-use .pdf sheet output to scale.