Help making a composite surface

[Lyonstp]

I don't know why this is hapening, I've done this in the past and it worked out diferently.

I have an existing surface, I also created a second surface using feature lines and "grade to surface". Now I want to combine them and make a composite surface. So, I create a new surface, paste the existing surface and then the new proposed surface. The problem is when i do this they merge but the center of the existing surface dissapears.

See image for reference

How do i maintain the existing surface while still managing to add the proposed?

[Lyonstp]

just posting other pics here

[wfberry]

Use the search feature of Civil 3D and search for "infill".

Bill

[Lyonstp]

I know about the infill function, but what I actually need is the existing surface within the proposed dikes to show up. right now it is just blank space. I could use the infill function if it comes down to it but it will give me inaccurate volume calculations (since it will be a flat, infilled surface)

[sjg]

Turn on your borders in your surface style for the proposed surface, try adding a hide boundary on the inside of the proposed surface.

[Lyonstp]

I just did this, and I am getting the same result. It clips out the middle (existing surface) even if i DONT have a hide boundary.

I've attached an image, the existing surface is shown in orange, the proposed dike in blue and the composite surface in green (which contains the proposed dike surface and the existing surface). as you can see the existing surface in the center of the dike does not get included when added to the composite surface.

[Hidden_Brain]

if you are adding an outer boundary to your proposed dike surface and also a hide boundary in the middle, reorder in the surface build operation to have the hide boundary addition after (below in the list) the outer boundary addition, and see if that makes a difference.

[Lyonstp]

I'm not adding any boundaries for my surface, the hide boundary was proposed as a solution but it did not work so i removed it.

[troma]

Try adding a show boundary for that middle portion.

[Hidden_Brain]

interesting, i am seeing the same behavior as you are. even when i create a new blank surface, paste EG into it, then use the perimeter of the middle portion (toe of slope) as the outer boundary, and then paste that into the combined surface, i still cannot achieve desired results. with or without an infill on the FG, same deal.

sorry, not the answer you were probably looking for, hopefully someone wiser and more knowledgeable than I am will soon weigh in.

[Hidden_Brain]

i cannot make the combo show EG in the middle using a show boundary. it appears the show boundary on the combo creates similar result as adding an infill.

[troma]

Perhaps then the only workaround is to make a third surface. Paste EG in and add that toe of slope as an outer boundary. Then paste onto the composite.

[Hidden_Brain]

i tried that too (please check my earlier post), same results. i cannot make it work at my end.

[troma]

Sorry, missed that point.
Got me beat. I'm sure it's worked like one or more of these combinations for me.

The only other combination I can think of is to make a new surface and paste in the **** and then the centre surface. Then make your combination surface and paste in EG and then this '**** with centre' surface.

[lee · Accepted solution]

I've had the scenario before.  What I did is first make a copy of the existing surface. Took my finished grade surface and extracted the surface border.  Took the border and used it as an outer boundary for the existing surface copy.  Then for your composit surface, paste the original eg, finished surface and then the eg copy.

Lee

[Hidden_Brain]

lee,

i think i did the steps that you are suggesting, with the only difference being that i created a blank surface and paster EG into it, instead of making a copy of the EG. I could not make it work with adding the outer border on the blank surface (pasted EG), and then finally pasting it into the combo in the following order: EG, FG, blank surface.

I can try making a copy of EG and repeating the same steps to see if it makes a difference.

[BrianHailey]

Here's the approach I would take. If you did something similar without it working, post up your surfaces and we'll take a look at it.

[Joe-Bouza]

take the bottom FL of the dike>> create a new surface EG-bottom on dike, use the FL to make an outer boundary to the Dike. Paste EG-bottom to the composite

[lee]

What you do with the copy of the eg is use the (extracted) border of the FG surface as a outer boundary for the eg surface copy.  Thats the surface that will fill in the area you are wanting with eg contours.  Thats why when you are creating the composite surface you past it last. 

Should work.  I know it works when I have your senario.

Lee