from Civil to Inventor

The Autodesk enthusiast exile

Surface Patching

In this exercise we will begin with the data imported in the previous posts, Import points scenario.

In this post we will Import a point group into an existing surface, and edit the surface to get rid of any legacy data. 

We will cover:

  • Cleaning out legacy points from a surface
  • Importing Point Groups into a surface
  • Exporting and Importing XML data for surfaces

Cleaning out legacy points from a surface

Importing a point group into an existing surface is quite easy. It can be very messy. Preparation is the key to a smooth application. Some of the key issues are:

Where will the data go, and How will the application try to apply it

With a little practice, you should begin to see how the application will insert and connect the data.  You will then be able to avoid problems before you walk into them. 

The surface we are discussing has separate Object and Display layers, so let’s thaw the Object layer “Surfaces-Existing”. 

Notice the REF- Surfaces used here to show the individual parts of the composite Existing surface. In the past when we added large amounts of data to a surface, we created the surface to be added first. Then after it is complete (and debugged) then we PASTE it to the final composite surface. The reason is to debug the new data separate from the final composite. Once the data is added to the composite, it is much harder, slower to edit, and difficult to visualize the problems. We XML save the reference surfaces. See last section for more information on this.

Note: in this exercise we are not creating a separate surface.  There are so few points being added, it is far simpler to add the data directly to the composite group.  You will have to decide which method is best for your particular need.  Only practice will give you insight.  Try it different ways.

We should change the Surface Display style to a visible and editable style. While editing a surface, the surface must display what you are editing. If you are editing triangles and points, then you need to see both. 

I always keep a few Editable styles in my template, plus I may create a few during a workflow.  This is what it looks like with the triangles, points, and contours. You should also note the sorted (blue) points that need to be imported into the model. Easy to visualize what and where we need to edit.


As you can see there is some legacy data in the area of the surface that the blue points will go. These old points need to be erased. With few exceptions, if the data coming in is newer and more complete that the legacy data, kill the old. 

To continue, we will select Delete Point method from the edit member of the Existing surface. Right Click on Edits under the Existing surface and select Delete Point.


The command line will prompt you to select your points. This is truly annoying because you have to command line each option unless you want to pick each point 1 at a time. I like Crossing Polygon. Type CP. Then it will ask you to pick the polygon shape.

While I am moving about looking for what to kill, I need to validate some info. 

Test areas against new data visible. Here we hover over a location near the point in question and read the pop up data for the surface. Existing says 15.3 near a 16.4 and climbing. Probably no longer good. It’s a gonner.Notice below the close knit data points along the contour. That’s how they got in, as contour data added, and are not valid. Contour points are always suspect. Also notice the selection polygon. When complete hit enter, and wait for the system to confirm what you selected. Then enter again.

Here you see the shelled out product. We did not kill the surface, just removed all the data in an area.


If you do, the surface WILL be destroyed in that area. When you add the data back in, the application will have a lot of trouble deciding what should be connected, and what shouldn’t. The result is 20 or so tiny dead spots, that all have to be manually reassembled.


Importing Point Groups into a surface

Now we add points from the topo group created.

Right click Point Groups option lying below the Edits option selected in the last step. Click Add. The system will show you a list of Point Groups, select the one you want. The vertices will be added based on the coordinates for the included data in the point Group. Nothing more, and nothing less. 

Now you see the triangles for the new data. SWEET. And easy.

Now to straighten out the problems. Notice the pretty mountain peak to the left in the above image? Nothing is perfect. 

Hover over the point information and the system returns the point data. This will get us the point number to investigate. It is correct. A few parallel shots might have been in order, what do you think?

After deleting 2 legacy surface points nearby, the surface looks much better. We swap a few edges and delete a few more points then it is time.

SAVE THAT DRAWING!!!!!!!!!!!!!!!!!! 


Export and Import LandXML

The Surface has been kind enough to hold on to every last edit you have made. You can add and subtract edits, like a selective undo. The thing is, we are satisfied with our surface. Why should we carry the luggage around with us? We need to get rid of them. Every time you do anything in this list, even when erasing data, you are adding more weight, more instructions, and more chances to crash. Get rid of it just as soon as you can.

Through the magic of XML you too can reduce your overhead.  Right click on the Existing Surface and pick Export LandXML.


The Prospector list comes up with the Existing surface selected. You will see only your data is selected this way. Pick OK.

Then indicate the name of the file to save. Yes save. It just so happens that a lot of others are waiting on this data, and we are using an XML share. This allows the data the update easily without VAULT. It also allows us to re-import the data and tie off the surface to the point of the import. Otherwise I would have 10000 edits easy in this file. There would be no way to open it.

After you select the file name, hit OK. In the case of a share, the Surface name must be identical from user to user. Don’t change the name once everyone is using it. This XML file must have a constant name, as other members of the team have surfaces pulling constantly from the share XML. If you save with another name, they will not get the data, but will think they did.

This XML will take 20-30 minutes to write. It’s dense. Just go take a break. When you return, it still won’t be done, but hey, it’s worth it.

Note: Most XML surface writes won’t take this long. This surface is just really heavy.

Note: The best way to share the data is Data Shortcuts. We are mentioning an XML share because we have to write the XML anyway. Look for another post on Data Shortcuts soon.


Now to finalize the adventure.

Immediately import the XML file back in. Yeah that’s right.


A browser will appear for you to select the XML file to Import. The system does not know what you are feeding it. If you feed it something else, well it’s …wrong.

The system will pop up a dialog asking you to confirm what it sees in the data, and then another to ask you if you are ok importing the data. (this is a bit simplified, but hit OK until it gives you what you want. Afterwards it will complete the import and tell you so.

If you check the surface properties, you will see there are no edits, but one snapshot. Leave the snap shot on. This keeps a record of what the system found in the XML file. Otherwise it will check the XML file when it feels like regenning the surface.  

Note: Large projects may get a bit of relief by removing the snap shot.

When the XML imports, it usually imports the edits as points. Right click on the Surface name, and select properties. Under the Definitions tab where you saw the snapshot, you will also find any stray data after the snapshot. Usually there is a point group. Right Click the point group and select remove. We want it gone.

Afterwards, close the properties dialog, and navigate to the point groups. At the top to the point groups, you should see the same group name you removed from the definition of the surface. Right click that group, and select Delete points. NOT DELETE, Delete points. If you delete the group, the points will fall into the _All points group and we will not remember what the point numbers are. After you tell it OK, THEN right click the empty group, and select Delete. The point group will go away as well. 

That’s it. The Surface is now a function of the XML and not the original data.

October 16, 2008 - Posted by | Surfaces | , , , , , ,

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