Hatching out a Slope Map

Jason Porter

All, Surface, Tag, Construction 0 Comment

I was teaching a standard Civil 3D class this past week when one of the students wanted to know how to create a slope map with hatches rather than just colors.  Their client requests slope maps with different hatch patterns representing different slopes. Apparently there are many users who need this same concept because the client in question happens to be a major city here in Texas and they require this from all their engineers.

The wheels began to turn and I came up with this method.

Beginning with the surface you are need of the slope analysis:

Select the surface, right-click and assign it a surface style that uses slope banding. Here I'm using the standard "out-of-the-box" Slope Banding (2D) style:

The problem is that this style generates AutoCAD solids to perform the slope analysis.  We need hatches.  So we need to modify the style:


In the surface style dialog box, navigate to the analysis tab Navigate to the Analysis tab, and change the display type from 2D solid to hatch solid:

Back in the surface properties dialog box > Analysis tab. . .change your analysis type to Slopes, edit the number of ranges you need, and push the down arrow to run the analysis.  You will then see your slope ranges. You can double click in the minimum and maximum slope ranges to adjust your slope values:


You will see a surface which looks like a standard slope map:


The issue now is that you have your slope map but you don't have any control over the hatches or hatch patterns.  To rectify this we must now extract the hatch data so that we can  modify it. FYI - this hatch data will no longer be attached dynamically to your surface.  So if you need to update the slope map you will have to go through this process all over again.

To extract the hatch data, select your surface and in the contextual ribbon you'll see the option to extract objects:


In the "Extract Object from Surface" dialog box verify that slopes is checked on and click ok:


Do not click anything else.  You're surface is still selected.  So now right-click > surface properties > information tab and set your surface to a "No Display" style:


You will be left with a bunch of solid hatches on your screen. Select one and view it's properties.  In this example I have a bunch of solid hatch patterns that are color 60:


Now I will select all the hatches in my drawing that are color 60 to modify them all at once.  Use the QSELECT command and set it to look at the entire drawing and find any hatch that has a color equal to 60:


You will see that all the hatches in your drawing that are color 60 are now selected.  Your contextual ribbon should now display the hatch editor.  Change the hatch style to your desired style, hatch scale, and, if need be, another color. Here I've changed the pattern from solid to ANSI37, adjusted the scale to 100 and left the color as 60:


You should then see your hatches appear with the settings you selected:


Repeat the QSELECT command for your the other colors.