DWG TOPO Problem

[dsw98]

Okay i'm having a problem getting a dwg file to convert into a 3d topo once I import it into Revit. So my question is, are all dwg site plans capable of being convereted into a 3d topo in revit or not? Thanks

[jeffh]

1 - DWG needs to have lines/polylines placed in 3d space (elements need "Z" value)

2 - DWG needs to be inserted into Revit as a model element. In the import dialog there is a check box for inserting into only this view. Make sure this is UN-CHECKED when importing the DWG.

If you follow the 2 rules above you should have no problem creating a toposurface from a DWG file.

[dsw98]

1 - DWG needs to have lines/polylines placed in 3d space (elements need "Z" value)

2 - DWG needs to be inserted into Revit as a model element. In the import dialog there is a check box for inserting into only this view. Make sure this is UN-CHECKED when importing the DWG.

If you follow the 2 rules above you should have no problem creating a toposurface from a DWG file.

Oh that was it. The check box. I havent' imported a site plan in a few years, maybe it's changed since that last time I did one. Thanks

[cliff collins]

With all due respect to Jeff---

Warning:

By unchecking that box, and Importing, not Linking the cad file
it will now be imported into every view in the project! Then it becomes difficult
if not impossible later to track all those imports down in every view. It also
bogs down the Revit model, as it has to keep track of the cad file in all views!

Instead, I would open the Site Plan view, LINK the cad file, and check the box
so it does not get imported/linked into every view. Make a new workset for cad imports
and place it on that workset.

Also, by Linking the cad file, if changes are made to it, you can update the link,
and then re-create the toposurface.

Another tip: You will need to set up a shared location / origin for the cad file and coordinate the location in x,y and z axes. Do this once at the onset and you'll be
glad you did later. There are many threads on this forum about how to set up a proper shared location in Revit. 2010 has a couple of new features for this: "project location"
and "survey location" which help in getting cad and Revit files lined up correctly.

Cheers.........................

[Joef]

I think you have to un-check that box or it doesn't work. (topo generation from dwg file) This was a controversial change a couple releases ago. You don't have to keep the drawing around once you have made your topo. If you just want the linework from the dwg you can remove it then link it back into the site plan only.

[jeffh]

I think you have to un-check that box or it doesn't work. (topo generation from dwg file) This was a controversial change a couple releases ago. You don't have to keep the drawing around once you have made your topo. If you just want the linework from the dwg you can remove it then link it back into the site plan only.

That is correct. If you import (or link) into only one view, then the DWG is a "drafting" object and has no 3d info in it. You will NOT be able to create a toposurface from it. Once the toposurface is created you can delete the DWG file from the project.

[Scott Womack]

That is correct. If you import (or link) into only one view, then the DWG is a "drafting" object and has no 3d info in it. You will NOT be able to create a toposurface from it. Once the toposurface is created you can delete the DWG file from the project.

Jeff,

This is true, however, you can link it in and create topo, versus importing it in. The other possible trick is to import (preferably link) in the cad file to a blank project. then create the topo surface. Acquire the coordinates from the CAD file. Link in your building, and place it on the site, and position it. You can then publish the coordinates to the linked building. Later you can link the topo into the building site. If you need to work on it there, you can always bind the topo file into your project.

[jeffh]

Cliff and Scott,

You guys are talking about strategies of managing DWG files and a building site within the Revit workflow. My response to the OP was to try and clarify why he was not able to generate the toposurface form the DWG.

I did not mean to imply any best practice workflows or advantages of linking over import.

(I do welcome the comments though, as I am working on a tutorial that covers this very process and the sharing of information with Civil 3D via ADSK file.)

[Scott Womack]

Jeff, I was just cautioning the OP, since DWG files have been 90% of the root of Revit files becoming unstable mid to late project, and of these site drawings from consultants have been 90+% of the root issue. Admittedly, I have yet to get a site consultant's file created in Civil 3D. Surveyor's drawings have been terrible in so far as stbility goes.

The workflow described in my post above has been delevloped in an effort to distance the consultant's drawing frile from the working architectural Revit file. Our projects routinely get from 100 to 200+ meg by the time CD's are issued, and instability can become a serious issue.

[cliff collins]

All,

I think Scott's workflow sounds very good.

I think it is a very bad thing that you have to bring a cad file into every view
in the project to be able to create a toposurface. This needs to be fixed.
That can cause serious performance issues, as Scott mentions.

cheers.......

[sbrown]

Once the topo is created, delete/remove the cad file. I suggest cleaning up a flat dwg for the site info needed. and a dwg with the 3d topos. So once you've created the topo, just delete it, then use the clean/flat dwg as you would any other dwg.

[cliff collins]

Hmm,

Easier said than done when the cad file is imported into all views!!!!!!!!!!

We have over 120 views in a current project--not the best utilization of someone's
time to go and manually delete the cad import from all these views.

This is why we REQUIRE all cadd files to be LINKED.

LOL

cheers............

[jeffh]

Easier said than done when the cad file is imported into all views!!!!!!!!!!

We have over 120 views in a current project--not the best utilization of someone's
time to go and manually delete the cad import from all these views.


By unchecking the box and importing into all views you are simply importing the DWG lines as "model" lines. Model lines (by definition) are visible in all views. There is still only one instance of the lines from the DWG import. If you later delete the imported DWG, it is removed from ALL of the views at once. You do not have to go in to each view and delete it out???? If you are having to delete out a DWG import from each view then something is wrong or someone imported the DWG into each view seperatly.

The model lines are what is import to the process of creating the toposurface. If the lines are imported into "current view only" they are "drafting lines" which by definition are not 3d and can't appear in multiple views.