<![CDATA[vectors "jumping" unexpectedly]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly
Mon, 29 Mar 2021 08:23:05 +0000Fri, 26 Mar 2021 14:40:52 +0000Zend_Feed<![CDATA[Note: Points work. So a turn around is to have points as output which I then must link to create vectors. But it doesn't show what is the direction of the vector, so it takes time to find this direction by other methods...]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301778
Sat, 27 Mar 2021 07:43:37 +0000<![CDATA[Note: This problem happens in 3D only.]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301804
Sat, 27 Mar 2021 07:53:01 +0000<![CDATA[I think it is an Application to computer graphics of https://en.wikipedia.org/wi... so it is not possible solve the problem as you hope]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301806
Sat, 27 Mar 2021 10:15:32 +0000<![CDATA[I have attached a simple example of this phenomenon. When you apply the tool "force from face" (in the menu) to the faces of the tetrahedron, successively, the element's values are correct in the algebra window and the points are shown correctly, but the vectors are all shifted to the last element modified...]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301808
Sat, 27 Mar 2021 11:04:34 +0000<![CDATA[This is an interesting theorem :) However, I think there is no math difficulty in joining points by a vector. If the points exist, we can always join them... (As I do by thand as a turn-around) So it looks more like a problem of how user tools handle vector outputs.]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301812
Sat, 27 Mar 2021 11:08:58 +0000<![CDATA[Maybe try constructing the tool in a different way]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301830
Sat, 27 Mar 2021 17:49:10 +0000<![CDATA[I can not open your tool; what should the tool do?]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301850
Sat, 27 Mar 2021 21:35:25 +0000<![CDATA[Oh... The mystery thickens... I tried opening the tool in "manage tools/open" and it shows only undefined objects!!! And yet the tool works!!! I never saw that... Attaching the file, with the tool applied to another polygon. (please open the 3D view, all objects are in 3D) Thank you so much for looking into this!]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301856
Sun, 28 Mar 2021 05:37:48 +0000<![CDATA[Now I have made another tool doing the same thing. This is the script: First I make a plane in 3D to be sure all objects will be 3D Then I make a polygon on this plane (here it's a pentagon). The name is poly1 Now this is the script: O=Centroid(poly1) P=O + PerpendicularVector(poly1) e=Vector(O, P) Now the output objects of the uset tool are e, O, P The input objects selected automatically are the 5 points of the pentagon. BUT I remove these 5 points and select the pentagon instead. (This is very convenient as the tool can be used with one single click with any polygon) And that's it. PLEASE NOTE that the tool is working, in the sense that all the output objects are defined, and correctly defined, in the algebra view. It is only an issue of display of the 3D vectors when they are the output of a tool... Slightly irritating... ;)]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301858
Sun, 28 Mar 2021 05:49:28 +0000<![CDATA[If I unclick "show object" for the output vectors and create new vectors from the output points it works fine. (This is what I do in practice). Also I can still use the VALUES of the output vectors, which are correct. It's just that they are shown from the wrong starting point.]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301860
Sun, 28 Mar 2021 05:53:08 +0000<![CDATA[tienes razón: he construido una herramienta desde el principio para hacer el vector a partir de un polígono y cuando la uso varias veces me redefine el punto centroide de los polígonos sucesivos al último de ellos y me pone todas las direcciones perpendiculares al polígono en el mismo punto, y tampoco puedo editar la herramienta solo puedo concluir que no es posible hacer una herramienta empezndo con poligono en 3D y que funcione.]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301866
Sun, 28 Mar 2021 11:05:15 +0000<![CDATA[No it really works. All the objects in the algebra view are created as expected. It's only a visualisation issue for vectors in 3D. Also it has nothing to do with having the input as a polygon. If you keep the 3 points (or 5 points) automatically selected by the wizard, it does the same anyway: The vectors are all shown starting at the last occurrence of the tool, instead of staying where they have to.]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301868
Sun, 28 Mar 2021 11:30:54 +0000<![CDATA[There is a slight ambiguity with the representation of vectors in geogebra: Geogebra tries to encode the starting point together with the vector, but without showing it explicitly. The only way you can see it has encoded the starting point is when the vectors are shown in bold in the algebra view. This feature is extremely useful. Otherwise if we want to encode a vector's location we have to keep a list of points in parallel. However the handling of this feature is tricky at times. Some operations loose the location, and the resulting vector is shown in normal font (not bold). It is tricky when such vectors are input or output of user tools...]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301870
Sun, 28 Mar 2021 11:35:40 +0000<![CDATA[En el adjunto hay dos herramientas construidas siguiendo exactamente los mismos pasos una de ellas se puede abrir/editar y la otra no y ambas no tienen vector alguno, así que las herramientas para polígonos 3D no funcionan como las herramientas para los polígonos 2D]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301878
Sun, 28 Mar 2021 14:35:05 +0000<![CDATA[Thank you Mathmagic, that's good to know... But why tools with 3D polygons can't be edited? Mystery... The 3D modules of GGB probably have some shortcuts that make them less robust than 2D... I used 3D user tools already but with scripts only. But for quick problem-solving, normal user tools are great! So I hope this problem will be solved one of these days!]]>
https://help.geogebra.org/topic/vectors-jumping-unexpectedly#comment-301912
Mon, 29 Mar 2021 08:23:07 +0000