Trimble Business Center

Thanks in advance for those that take the time to chime in . . . .

We are trying to accomplish a task that seems like it should be easier.  Please see attachment for discussion.

We have battered bridge supports that have limited geometric data.  We were able to build the top and bottom using data provided, but there is a construction joint at elevation 605.  We are trying to generate a box (as shown in cyan, provided by another firm, but we need to compute ourselves for confidence and liability purposes) at elevation 605 that is bounded by the exterior faces of the bridge support.  We have accomplished this in two different methods . . .but both are somewhat tedious methods.

1.  Create contour at elevation 605 on each face, then connect or reduce vertices but dimensions are not checking out when trying to clean up this data (no option to turn off contour smoothing may be causing the issue).  The theory is that each face 605 contour line should be four line segments with two vertices each, but there seems to be horizontal discrepancies and a lot of manual line editing to reduce vertices just to discover some anomalies.  A lot of tinkering for one rectangle box.

2.  Create planar surface at elevation 605, merge that surface with (for example) north face, choose 'keep minimum' and then snap a break line on the north face where the surfaces 'intersect' line is.  (See page 3 of pdf)  Repeat for south face and connect break lines by snapping.  Still a little tedious.

Any ideas are welcome.  We feel we have some pretty advanced BC-HCE users at our company and these are the best options we can come up with at the moment.

Thanks

Dean

Dean

I have recorded a short video of how I would go about this - maybe I am missing something here, if so let me know and I will think again, however I did the two things here and they seemed to work for me on a mock up of what you are showing in your PDFs - if you could send me a VCL of the Bridge Abutments then I can take a look at your data specifically to see where the differences are

1) You can create a Rectangle at Elevation 605

2) Once created make it a SUrface Model called Datum 605

3) Use the Surface Intersect command to calculate the point on each line of your Bridge Abutment at the elevation 605 - you select the end of the line as the coordinate, the Datum 605 surface as your target, the bearing would be the bearing of the line of the abutment and the vertical angle is the angle between the start and end points of the line (you can use Point To Point to calculate the Vertical Angle. Execute - this gives the point on line 1 - Repeat for each line to compute the 4 points and then draw a linestring between the 4 points to compute your shape and check it.

a second method I used was to create a Surface from the two lines and then to creayte a contour at Elev 605 (this you did also), and it creates more than one line segment between the two lines, because it crosses a Triangle Face - maybe when you created your Datum Surface you had it creating many points along each side ie many triangles and that is why you had many vertices - I just had the one which is easy to delect if you want to get rid of it, or you could just draw a linestring for the rectangle between where the contour hits the edges of your abutment. If you need to change how your surface is created for the Datum Surface - change the Project Settings, Computations, Surface to stop it from densifying the lines creating nodes in the TIN model.

Hope that this answers the question - let me know if this helped

Alan

Alan,

Thank you for your response.  You have shown a 3rd way to do it, the surface intersect command, and we speculated if that was the right command to be trying.  I have forwarded your response on to the drafter and I will wait to hear which method works the best and fastest with as little cleanup as possible.

Thanks again,

Dean