Category Archives: Coordinate Geometry

IP2 Update, ByRef and ByVal

Posted on 08/11/2011 by dougaj4

A recent comment pointed out that the IPPlaneLine function (intersection of a 3D line with a plane) in the IP2 spreadsheet was giving incorrect results.  This has now been fixed, and the corrected spreadsheet can be downloaded from IP2.zip. The problem turned out … Continue reading →

Posted in Arrays, Coordinate Geometry, Excel, Newton, UDFs, VBA | Tagged , , , , , | 1 Comment

Area from Vectors

Posted on 27/08/2011 by dougaj4

The previous post looked at User Defined Functions (UDFs) for working with vectors, including examples of functions to find the area of polygons defined by coordinates.  In this post the functions will be extended to find other section properties (such … Continue reading →

Posted in Arrays, Coordinate Geometry, Excel, Maths, UDFs, VBA | Tagged , , , , , , | 5 Comments

Dots and Crosses

Posted on 21/08/2011 by dougaj4

The comments from Bill Harvey in the previous post prompted me to have a closer look at the functions available in Excel for working with vectors.  Here is a complete list of them: =SUMPRODUCT() (Equivalent to the vector dot product) This … Continue reading →

Posted in Arrays, Coordinate Geometry, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 11 Comments

Section Properties from Coordinates Without VBA

Posted on 07/08/2011 by dougaj4

At the Eng-Tips forum there was a question asking for a calculation of area and centroid values from coordinates without the use of VBA.  In my opinion using VBA is much the easiest and most robust way to do it, … Continue reading →

Posted in Coordinate Geometry, Excel, Newton, UDFs, VBA | Tagged , , , , , | 13 Comments

PaulBourke.net

Posted on 23/07/2011 by dougaj4

Another link from Al Vachris: PaulBourke.net. The link above has a general subject index, and google site search; for a full list of the site content go to the detailed site index. Here’s what the author says about it: “The … Continue reading →

Posted in Computing - general, Coordinate Geometry, Maths, Newton, Ray Tracing | Tagged , , , | Leave a comment