Wednesday, December 28, 2011

Geomarker Civil 3D

In an earlier blog I already mention the geomarker and how the revit extension seem to use the geomarker to exchange date between Civil 3D and Revit. 

I do not think that that is a good point to use. Specially when you look at the following:

I have recorded a screencap from Civil 3D. I only have a surface in and I'll do the following:

  1. turn on the geomarker
  2. edit the geomarker
  3. put the geomarker to another position
  4. save the dwg

What you will see in the movie is that when you invoke the save command the geomarker jumps back to center of the site. I don't think that the center of a site is a handy point for exchange since if the site changes size the center point and so the exchange point changes...

A bit of googling on geomarker on got me this:

It would be really great if the geomarker would behave the same as the project basepoint does in Revit. Funny knowing Revit's problems with large coordinates I never thought I would suggest another system to use some of Revit's techniques.

If anyone else can shed some light on the geomarker and how to keep it fixed I would be very gratefull!

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Friday, December 23, 2011

True North it is

So once in a while you run into something that is completely obvious when you look back at it.

I have written before about the true north and project north issues with Revit. (It gives problems with linked files) I have asked myself before why bother with project north at all. Probably because of working in Autocad before. I tried to to the same in Revit. In Autocad you want lines to be horizontal or vertical, if possible.

But with all the nice tools in Revit it's not really necessary. Section are easy to draw, parallel to grid lines and elevations orient themselves perpendicular to walls. The only thing that's left are the floor plans. Some projects will probably look stupid if you don't rotate them. Some things might become difficult to read.

If you work solely in Revit and you have no need to link in other files than do use project north it's easy to setup. If you do need to link in site plans or something similar see if you can get away with it not setting up project north.

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Thursday, December 8, 2011

exchanging surface between civil 3D and Revit

Today we ran into another oddity in the whole coordinates story...

I like to set the project base point manually. I do this in civil. I choose a point with nice numbers and put a little x there. To get surfaces from civil 3D into Revit I like to use the Integration with Civil 3D extension. In order to exchange surfaces between Civil 3D and Revit I create an extra surface that has it's center spot exactly upon the project base point. This is a dummy surface for which I am sure that it will not move or change shape! (see previous post why I do that)

Today I had to check something and I didn't bother to setup my project basepoint on a nice round number. And guess what, it turns out that Revit didn't put the project base point where it is in Civil 3D but it moved it to a nice round number...

In civil 3D the ID of center of the surface is: (meters)
X = 235013.1029     Y = 580515.5750     Z = 0.0000

Revit creates a project base point at n/s 580515500.0  and e/w 235013500.0 (Millimeters)
You can also see that the project base point is off center. 

I redid the whole thing but then I used nice numbers in civil and then Revit did use the same coordinates....
So instead of these  X = 235013.1029     Y = 580515.5750     Z = 0.0000
I create the point at X = 235000.0000     Y = 580500.0000     Z = 0.0000

Recommendation: Create your own project base point in Civil 3D and put it on a round nice number! Create a dummy surface that has it center on your created project base point. Get only that surface into revit first and CHECK the project basepoint numbers!

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