Workshop 5 Notes, Week of September 22, 2008

ACCUDRAW, 3D CONSTRUCTION PLANES & DIGITAL TERRAIN MODELING

Note: This workshop focused on a number of digital terrain modeling methods. The primary method of concern is reflect in notes captured under item #4 below. The other methods are more advanced and extracurricular to the requirements of arch 541.

1. The Accudraw Compass
   
   
                
                 coordinate readout / entry in Accudraw
   
   1. XY(Z) axes
   2. Dynamic Coordinate Readout / Entry
      1. Precision input M:S (Master Unit : Sub Unit )
      2. AccuDraw Settings:Display – Display Coordinates        
      3. Spacebar or F11 – give AccuDraw input focus
   3. Context sensitivity to gesture
      1. Just type in distance
      2. Last distance remembered, PGup/PGdn distance cache for previous values used
      3. Popup calculator (+,-,*,/) Enter operation right into Accudraw box
      4. Variables (pi) and parenthetical expressions can also be used
   4. Spacebar change mode between polar and rectangular coordinates
   5. Composite distances (X, then Y) and trackings
      
      
      compass rotates to line
      
      
   6. Compass Follows you and rotates.
   7. Return to Top - T
   8. RQ – rotate quick (twist mayline)
   9. RE – rotate to element
      
      
      quick locks – geometric alignments
      
      
   10. Quick Locks – geometric alignments
   1. Enter – Axis lock established by typing "X", "Y" or "Z"
   2. Lock X, Y, Z
   3. Measured distances (and calculations)
   11. Shift Origin - Letter "0"
       
       
       
2. Snap shortcuts
   1. C (centroid, not just center)
   2. N (near, use with Axis lock for y=mx+b)
   3. I (intersect)
   4. K (divisor to subdivide element)

2. 3D Construction Planes

         

1. V rotation
2. T rotation
3. F and S rotation
4. Location and Rotation – Accudraw with snapping in 3D-space
   1. Build a 3D box…
5. O shift origin
6. Rotate ACS
7. RC – rotate to Current ACS
8. RX, RY, RZ axial rotations
9. RE – Rotate to Element in 3D
10. Type ? for quickkeys help

3. Polygon Mesh Objects:
       

            solid sphere with control vertices exposed by using the select tool

1. Create new file
   Surface Modeling Task menu           
   Create Solid Sphere
   Mesh Tools > Construct mesh
   Arrow Tool - Click to see mesh points
                           Click again on a point to edit / move
2. Unfold Mesh
   Mesh Tools > Modify Mesh > Unfold
   
   
   point cloud of head
   
   
   
3. Mesh from Point Cloud
   Tools > Annotations > XYZtext > Import
   Demo Head – Point Cloud.txt
   Construct Mesh – From Points

4. Terrain [KEY METHOD USED IN TERRAIN MODELING]

1. Open Carr’s Hill.dgn from the classes folder.
   
2. Rotate to view 3D survey data – typical of GIS data received from municipality
3. Change to Land Surface layer
4. Selection tool – open triangle – select by layer – Index, Intermed
5. Surface Modeling > Mesh Tools > Create Mesh from Contours (creates digital terrain modeling in minimum number of steps).
    

[ADVANCED METHODS EXTRACURRICULAR TO ARCH 541]

5. Terrain from Image File: New CAD File

1. Image underlay –
   Utilities / Image / Display – get Topo2.jpg
   
2. Scale – 1”=300’, 7.5 x 12 inches in paper size
   Calculate area of the map
   
3. Close the image
   
4. Draw rectangle at proper size
   
5. Use accudraw to perform the calculation
   
6. Fit View
   
7. MDL Load Civtools (tool available for download from website)
   
8. [P] tools – parameters – set major/minor interval and colors/layers
   
9. Choose first tool – place contours
   
10. Type curve, planar
    
11. Set current elevation – 600 – and draw
    Keep going up the mountain.
    
12. Mesh Tools – Construct Mesh – From Contours
    
    
    

6. GeoPak Site [See more detailed description of this method under digital terrain modeling (2006 workshop notes)]

     

      digital terrain TIN mesh from  Mountain.dgn file generated by Geopak.

1. Open File Mountain.dgn
   Activate Bentley Civil (Applications Menu)
2. Change active layer to Default.
   
3. Turn off all layers except contours
   
4. Extract Graphics (contours, layers, view, Process)
   
5. Build Triangles
   
6. Load Features – Triangles – display only
   
7. Analytical extractions:
   Load Features
   Contours (5, 20) (minor, major)
8. Height / Slope
   Mode Elevation
   Mode Slope (single point and slope between)
   Slope Area tool          

1. Elevation – range 620-1000, increment 20
   
2. Slope % - range 0-100%, increment 5 (open slopepercent.rng file)
   
3. Aspect – open aspectrange.rng file
   
4. Drainage Tools
   Watersheds (first tool)
   Drainage Patterns
   Downstream and upstream traces
   Flow arrows diagram (arrow size 20)
   Ridge Lines and Sump Lines
   
5. Visibility tools (turn off contours layer)
   Line of sight (visible (yellow), not visible (dark gray)
   Surface points / Surface Lines / Surface Regions