Sometimes you don’t to show existing ground beneath proposed grade. While a hide boundary is a relatively simple thing if you’re working in the original file, you can’t modify a data reference. And could pull out a mask, but that can get a bit convoluted if you’re trying to punch a whole that’s not a nice simply rectangle. So what’s a linework-obsessive Civil 3D user to do? Well, this one reaches in to the old bag of tricks that don’t always work nicely, but work when you need them. See my solution after the jump.
Here’s my existing ground surface
Nothing too exciting, but a fair number of contours running across a smallish site. Drop in the proposed surface, and it gets pretty busy as you can see here:
The contours are also generally in the same directions, and in this client’s pen setup, they were pretty similar in appearance, so they wanted to mask them out. I’d convinced them to use data shortcuts instead of putting everything in one file (really not that hard of an argument, but sometime it can be,) but now we were stuck. I didn’t want to cut a hole in the surface, it would be useless for profiles. I didn’t want to kill the connection to the source, that’s a bad idea. The AECCLINEWORKBLOCKTOSHRINKWRAPMASKOFTHESHROUDOFTURIN command doesn’t even work on surfaces. Every other C3D object, that would be my solution.
Then it hit me, WIPEOUT.
Now, I’m not a fan of the wipeout. They give people fits and sometimes blow up depending on your plotter merge settings. After a few seconds of discussion with the crew though, I think this will work for them, maybe it will work for you.
First step, modify your FG surface style to display a border, and be SURE that style is set to Flatten Elevation to 0. When you use surface extraction and grab the border, this will give you a simple polyline. Extract, then close that pline with PEDIT. Type WIPEOUT at the command line and you’ll have the option to convert the new pline to a wipeout. When you hit OK, you’ll be left with something like this.
You might need to use the WIPEOUT – Frames option to turn it on, but grab the wipeout and use draworder to send it to the back. Then send the EG surface to the back, and you’ll be left with the last image. You can then toggle the wipeout frame off and you’ll be set to go. I know it’s not perfect, and there are some plotters that will balk at wipeouts, but it was what I could come up with on the spot.
What solutions do you have for sticky display problems? Share in the comments below!