Category Archives: Coordinate Geometry

Update to Glob_to_loc3 and Loc_to_glob3 functions

Following a comment here I have updated the Glob_to_loc3 and Loc_to_glob3 functions to deal with some problems when the local longitudinal axis is parallel to the global Y or Z axes.  The IP2 spreadsheet, including the revised functions, can be downloaded from: … Continue reading

Posted in Coordinate Geometry, Excel, Finite Element Analysis, Frame Analysis, Newton, UDFs, VBA | Tagged , , , , , , | Leave a comment

Nearest Lookup Function

The Excel Lookup functions (including VLookup, HLookup and Match) all allow for an “exact” or “closest” match on numerical data, but the closest option has a number of problems: The data must be sorted For VLookup and HLookup the data … Continue reading

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IP2 and IP2_py

The IP2 spreadsheet provides functions to calculate: Intersection points of 2D lines or polylines Intersection points of 2 circles, or a line and a circle Intersection circle of two spheres and intersection points of 3 spheres 3D centre point of … Continue reading

Posted in Coordinate Geometry, Excel, Link to Python, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , , , | 4 Comments

Dividing shapes into layers

For reasons that will become apparent in a later post, I need to rotate irregular polygons, defined by the coordinates of each corner, by a specified angle, and then split the resulting shape into horizontal trapezoidal layers. I have written … Continue reading

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Global to Local for plates (and three node beams)

The Glob_to_Loc function (see Converting from global to local coordinates (and vice versa) ) converts forces and deflections of a beam from the global coordinate system to the local system, defined by the longitudinal axis of the beam and a rotation angle … Continue reading

Posted in Coordinate Geometry, Excel, Finite Element Analysis, Frame Analysis, Link to Python, Maths, Newton, Strand7, UDFs, VBA | Tagged , , , , , , , | 3 Comments

The angle between two vectors, Python version

I posted a VBA function to return The angle between two vectors, in 2D or 3D last year, and have just discovered that Python and Numpy are lacking this function.  Since all the suggested code I found in a quick search used: Cos θ … Continue reading

Posted in Coordinate Geometry, Excel, Link to Python, Maths, Newton, NumPy and SciPy | Tagged , , , | 10 Comments

Xlls, Maths and Plots; some useful links

Two from regular commenter here, Keith Lewis: Excel xll add-in library: This is a library for creating xll add-ins for Excel from 97 through 2013. It makes every feature of the latest Excel SDK available to you including the big … Continue reading

Posted in Coordinate Geometry, Excel, Link to dll, Maths, Newton | Tagged , , , | 3 Comments