With the appearance of Space Scanners in the Construction Industry Scene, I was recently presented with an As-Built derived from Point-Clouds. NOT A SINGLE WALL IS SQUARE OR PLUMBED on the DWG.
Realize that nothing in the “real world” turns out squared nor plumbed. Just as certain that a wall-plane is not “straight” even though the resulting CAD shows the wall to be perfectly straight in the field.
Questions:
How do designers determine which plane to follow when walls need to meet one another in something “near” to the perpendicular? Do Designers, for the sake of drawing, “average” out what X and Y should be?
Any Pro’s out there confronted the conundrum of designing/drawing off-axes? Any pointers on how to push through such workflow process in SKP?
I’ve uses a Leica Disto and drawn in the field for years. Point cloud or no point cloud, I’ve always resorted to at least some idealization of measured existing conditions. Here is a picture from Stangl Associates presentation at 3D Basecamp last September. They are building off a point cloud largely by eye in this demonstration, but compared to my own experience, I would start eyeballing something like this, and then choose some idealized number to type in to keep some consistency and sanity to the objects. Then when it comes to designing, you have to be constantly aware that the model is idealized and you have to allow for error.
You have to have an extension. Stangle used Undet, which brings the pointcloud in SketchUp as a 3dimensional image, which can be clipped to concentrate on (smaller) parts of the pointcloud.
This is a paid extension.
Trimble has a free extension which opens the pointcloud outside SketchUp, you can select walls or points in the pointcoud and send them to SketchUp as Guidelines and points.
Thanks Mike: Fact is I received a DWG from the Surveyor as opposed to a Point-Cloud file. Don’t really want to immerse myself in Point Cloud Topology just yet precisely because it seems to be an “Acquired-Art” open to the CAD operator’s “interpretation” at this point.
That’s precisely were my question lies. How/Who sets Axes if at all?
I guess you will always have to have a reference point.
Depending on the scanners and position sattelites, there is more or less accuracy.
At some point, one has to agree on some ‘fixed’ location:
For instance the intersection of grid A and 01 at the level of the finished floor of building X.
Yes, that’s a still picture I took at the presentation. I don’t remember if it was recorded, but it might have been.
I guess I would treat the imported geometry more as a graphic and try not to snap to it. Work to your own geometric grid. In my confusion between programs, I’m probably thinking of PowerCADD where you can turn snapping on/off on a per layer basis, but I’m not remembering any similar feature in SU. Is there a way to ignore snapping on a select number of object? I’m not remembering one.
