Combining Topography

[Anonymous]

Hi All,

Has anyone out there ever successfully combined two sets of topography data into a single ground surface?

Basically on this project we have some accurate topography data within our site boundry and a less accurate data set that covers our site plus a substantial amount of space around our site.

I would like to place the accurate site data within the "near enough" data that surrounds the site.

Thanks in advance

GavoGarmo

[J450NP13]

Combine them how?  What format are they?

Just import both as different objects....

[Anonymous]

We currenly have two types of topography data for the same project. But I need to finish with a single combined surface.

One set is a 3D representation of the topography within the property boundry only. This data is contractually what we will be basing our design around.

The other set of data is a non contractual Lidar data set that covers the area within the property boundry and a substantial amount of land outside and around the property boundry. 

We have to use the contractual data with the boundary but we would like to attach the data from the lidar set that represents the land outside of the boundry.

A bit like cutting out a cookie with a cookie cutter and then placing it into a different cookie's hole. 

[chrisplyler · Accepted solution]

Place both sets as topography. Use the Massing & Site > Split Surface tool to cut a hole in the larger set that matches the smaller set. Select and delete the "hole" element you created above. The smaller set should now fit within the larger set. Then try using the Massing & Site > Merge Surfaces tool to join them together, although this may fail to produce an acceptable continuous surface if the edges don't exactly match up.

[Anonymous]

Hi,

Thank you very much for the reply. As you predicted they didn't merge perfectly but it certainly is close enough for my needs. Great stuff!

GavoGarmo

[Anonymous]

If it's any use to anyone else:

I've managed to get a better result by offsetting the cut line 500mm inside the area within the boundry, that way the merge surfaces has an overlap and can combine the surfaces to make a single smoothly connecting surface. Not super accurate, but looks more presentable.

Also for people struggling with making the cut in the first place, you need to export the cutting toposurface as dwg, then insert it back as CAD, that way you can select the edges of the surface with the pick line tool (and then offset 500mm)

[chrisplyler]

Good tips!