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How to create a 3D surface to create a solid model of a building-site.

By Brendan A. Creaner on 22 Oct 14:18 3 answers 2 comments

I'm trying to create a 3D surface to create a solid model of a building-site - to check blockages by the new building of scenic-views etc.
I've tried to import a 'point-cloud' of data from a theodolite-survey of the site - which has been processed in MS Excel into 3D coordinates - e.g. 312 295 102 meters. Solidworks seems to convert this data into mm and, while seeming to preserve the 'relationships' between points [i.e. the shape of the cloud], seems to dump the cloud of points randomly near the origin - i.e. one corner-point which was at 312 295 102 [m] is now located at 2.7 3.2 -4.6 [mm] and it's now only 3mm form a point which had the coordinates 310 294 102.5.
How can I import the original data into a Solidworks Part Document at its original location and size? SW DOES offer controls for the cloud 'alignment' - but I can't understand how to use these controls to put my cloud where it should be - AND at the right scale!

Attachments

SW Corrected XYZ Coords.txt, 2.22 KB
Download

3 answers

  • Robert H.
    Robert H. almost 2 years ago

    It's slicker to get it to come in at the right place and to the right scale, for sure, but failing the cloud alignment 'controls', you might try moving and scaling the surface post-import to get it exactly right. It would only add a couple easy features to your model.

    Interesting work, it sounds like! I took a screenshot from Google Earth of my property and inserted it as a sketch picture to start my model, but I don't have much contour to worry about, just the property shape and existing structures. I'm using it for forest garden design to aid in the layout and placement of 'over-yielding polycultures'.

    Point cloud site contour sounds much more interesting! Wish I had a plot of my property, but it's pretty flat to begin with so not terribly necessary for what I'm doing.

  • Brendan A. Creaner
    Brendan A. Creaner almost 2 years ago

    Thanks for the reply, Robert!
    I too used the 'Sketch Picture' as the base of the model - in my case it was more relevant to use an official Ordnance Survey download as the base picture on the XY-Plane. I moved the picture-file around until the key points matched the last 3 digits of their coordinates with the position on the XY-Plane of the Solidworks model.
    At the NE corner of the site, the elevation is about 115m above Sea Level and at the SW corner, it's about 99m - so this site is very far from flat! I'm still hoping to create a solid model to represent it.
    Your idea of moving the 3D Surface to its 'right' position after creation is ideal - BUT, as yet, I can't even import the Point Cloud at it's original scale - it's coming in as millimetres! Perhaps more relevant is the problem that I can't seem to FIX the points in space - which would be an essential element in deriving a contour-map from the final model [whatever the scale!].

  • Brendan A. Creaner
    Brendan A. Creaner almost 2 years ago

    I eventually did it the hard way! I made a 3D sketch of all the surveyed points and then created 3D-splines running from boundary-line to boundary-line of the property. Then I created a boundary surface from the end-lines, with these splines as Guidelines. This surface was NOT smooth and DID NOT resemble the ground surface. I had started by trying to join the survey-points with the splines - but these were too jagged, so I detached the spline control-points from the survey-points and smoothed the splines with new control-points set at 3D locations 'near' the surveyed-points. The new splines [as seen from above] ran roughly straight from end to end but conformed to the vertical variations in the ground surface. This made a Solidworks surface more like that of the terrain - but hardlly precise as I had to guess at 3D coordinates for control-points a few metres from those surveyed. Once I had an acceptable surface, I just extruded a sketch of the site-boundaries up to it and created my solid model! Now I can check sight-lines and draw a contour-map of the site. Whoopee!

    Attachments

    Rocheshill Site-3.SLDPRT, 7.54 MB
    Download

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