Here I take a 6.6 x 6.6 km piece of the real world and turn it into a 22 x 22 cm model. This translates to a 1:30.000 scale.
Load the DEM into the Table of Contents.
Draw a rectangle defining the area of interest. Choose some nice round dimensions in whole metres - it makes things easier.
Right click the DEM > Export Data.
Choose “Selected Graphics” in “Extent” and “Use Renderer” under “Output Raster”. I set the “Cell size” to “4″ to get a reasonable file size for a 6.6 x 6.6km square.
Select “TIFF” as “Format”.
Repeat the export process, but uncheck “Use Renderer”.
Not the difference between High and Low values, this is needed in AccuTrans.
The reason for exporting two different files is because Accutrans can only read the rendered TIFF-file, but to get the correct height values the unrendered version is needed with ArcMap.
Open the exported TIFF file by going to File > Open DEM > Bitmap to DEM.
Set “Multiplier 2″ to 1, and “X and Y Spacing” to 1 as well. OK.
Click the “->3D” button. The vertex interval should autoselect to something reasonable. In this case “4″ resulting in 339,488 triangles. OK.
Go to Tools_1 > Adjust Object. Click “Calculate Scale”. Select X axis and enter “220″ into “New Size”. Calculate. OK.
Click “Scale”. The dimensions will update, but the image displayed will remain the same.Â
Click “Calculate Scale”. Now take the delta-height measurement (divided by ten) from ArcMap and enter it into the Z-axis box (in this case 6,1 - corresponding to 61m). Calculate. OK.
Enter “1″ into the boxes for “X” and “Y” and leave the “Z”-measurement as it just was calculated. Click “Scale”.
The model now is 1:1:1. Click “Set Min at 0,0,0″ to get things straight.
Click the “Extrude” button.
Enter the material thickness minus the z-height of the surface to be milled. This should be a positive number! Click “Extrude”. Select “Flat Bottom”. OK.
The z-height should now be shown as the thickness of the stock material.
Go to File > Save As > StereoLithography (Binary).
Based on this:Â http://www.cambam.info/doc/plus/tutorials/3DProfile.htm
Object moved, so the topmost point is placed at z=0.
Profile 3D Method: Waterline Rough
Lead In Move: Spiral, Spiral Angle: 3
Cut Ordering: Level First
Profile 3D Method: Horizontal
Roughing/Finishing: Finishing
I decided to cut the model into four pieces and cut one of the 11x11cm pieces.
Rouging took 2h25m and the finishing took 2h50.