Lecture Outline
CREATE SURFACE MODEL
“AutoCAD Civil 3D 2010”
Harry Ward
Prentice Hall publishers
Chapter 2 Exercises 2:1-5
Start C3D, close opening Drawing 1, open drawing “chapter 2-a.dwg”.
1. INSPECT THE DATA FILE
This is ground data collected by a field crew on the site of a road to be designed and built.
There are two types of objects in the dwg:
(1) break lines on the “DTM BREAKLINES” layer – these are 3D polylines collected by the field crew along lines where the topography “breaks” slope.
It’s clear that there are existing major roads, minor roads/drives, a cul-de-sac, a major stream, minor streams, an existing building pad, etc.
(2) ground points on the “DTM POINTS” layer. These are “key” points between breaklines – high points, low points, general points as selected by the field crew. These were inserted into this drawing as a 3D block with a standard symbol and X,Y,Z coordinates. The third layer is empty, turned off.
2. DEVELOP SETTINGS
TOOLSPACE, SETTINGS, DRAWINGS, SURFACE, LABEL STYLES, CONTOUR
We will now set the label styles for the contour lines we’ll develop for this surface.
STANDARD, rt. Click, EDIT, a dialog box opens.
LAYOUT tab: notice property list, and current assigned values for each property.
Under category TEXT, choose CONTENTS, pick its current value, pick “…”, the editor dialog box opens, erase info in the right window.
Pick PRECISION. Currently contours will be shown to .001’, too many decimals, pick the value, select “1”.
Then pick “gray arrow” to populate the window, OK. The labels will now be shown to the nearest foot – see preview.
GENERAL/LAYER tab. Right now, it’s set to place contours on Layer 0. Pick the value and “…”.
Make a NEW layer, pick NEW. Under the value for Layer name, type “C-Topo-Labl”. OK. OK.
This will place all contour labels on this new layer.
This is just a short demonstration of the many settings that can be made in C3D.
2-3. SET UP SURFACE
Pick SURFACES from ribbon, CREATE SURFACE.
With this series of operations, we will create a TIN surface from the surveyed breaklines/points.
TYPE: TIN surface (a grid surface is often called a DEM with an even rectangular grid, volume surfaces are created during volume computation processes).
Pick the value for NAME. C3D will assign counter numbers to surface names Surface1, Surface2, etc. but we will name it “EXISTING GROUND”. Pick value, type “Existing Ground”
Now we’ll set the layer. Pick the icon at right of Surface Layer. Pick the icon to right of Base Layer Name. NEW. Enter C-Topo.
OK, OK.
Now well add a “suffix” of the Surface Name to the Layer Name. Pick Modifier, Suffix, in the Modifier value, enter “-*”
At the end of the C-Topo name a dash will be added and then the “wild card *” will add the Surface Name. OK
Enter “Existing Ground” for description. OK. Now TOOLSPACE PROSPECTOR see the new surface has been created, and the new layer has been added to the dwg.
2-4. BUILD SURFACE
TOOLSPACE/PROSPECTOR expand the new surface, expand DEFINITION.
Since our field data file consists of breaklines and blocks for the points, we have to add these objects to our surface’s definition.
Rt. Click on BREAKLINES. ADD.
As a description, type “EG” for existing ground. TYPE: Standard. Set Mid-ordinate distance 1.0 ft. This means that or curved break lines, triangles for the TIN will be created so that the lateral spacing between the tin straight line and the curved breakline will not exceed 1.0 ft. This will determine the number of triangles created. The lower the number, the more triangles. OK.
We have now added our field measured breaklines to our new surface model.
Now we will add the ground point blocks to the surface.
TOOLSPACE/PROSPECTOR, EXISTING GROUND, DEFINITIONS, rt. Click on DRAWING OBJECTS, ADD.
Object points: choose BLOCKS.
Description: “EG”, OK. Notice COMMAND LINE prompt: Select Objects. Select all objects (include breaklines OK, the filter will pick only the point blocks)
Now the TIN surface is created with a yellow surface boundary.
Inspect dwg.
2-5: DEVELOP CONTOURS
Now make the TIN triangles and contours visible.
TOOLSPACE/SETTINGS/SURFACE STYLES/STANDARD/rt. Click EDIT. Turn on various aspects of the surface model to visible.
You can also change colors.
Now we’ll add contour labels.
SURFACES/EXISTING GROUND/ rt. Click ADD LABEL
In dialog box, LABEL TYPE “Contour – Multiple at Interval”
ADD/now see COMMAND LINE prompts? 1ST POINT --Pick any point above the model/2ND POINT – pick any point below the model/ INTERVAL ALONG CONTOUR, enter 500/ ENTER.
Inspect the dwg. See the manor and minor contours. See the labels. The labels are on the layer previously created. Turn on/off.
This now added contour labels to the surface contours.