How can you change the viewpoint of perspective (to infinity) in a 3d plot?

asked 2018-01-29 11:43:53 +0100

al
21 ●3 ●6 ●11

updated 2018-01-29 13:07:05 +0100

I am plotting a function with a large z coordinate, so it has a rectangular solid box around it which is square in crossection and very long in height. If you rotate it to view from the end you don't see the orthogonal projection onto the square, since the solid framing the graph is rendered inperspective from a viewpoint which is not infinity. I tried aspect_ration {1,1,1] but that doesn't correct it. Any ideas ???

PS I'm running this ion the Cloud - I can't get 3d plots to run in my own notebook yet, and anyway right now my notebook isn't working at all- see other question !

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Please give us some code, using a constant function or something like $$(x,y)\to \min( \ \exp(1/(x^2+y^2))\ ,\ 10^6\ )\ ,$$ and the name of the viewer.

dan_fulea ( 2018-01-29 12:52:41 +0100 )edit

That's related to the question:

https://ask.sagemath.org/question/384...

I don't know any simple way...

pang ( 2018-01-29 15:08:22 +0100 )edit

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answered 2018-01-29 18:10:03 +0100

tmonteil
27423 ●31 ●204 ●517 http://wiki.sagemath.o...

To get isometric projection when viewing 3d plots on the notebook (with jsmol):

right_click on the background close to the picture to let a menu appear
select "style" in the menu
uncheck the "Perspective Depth" box

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Thanks for the answer! I am using the Cloud with the command show(list_plot3d,(x,-2,2),(y,-2,2),aspect_ratio = [1,1,1]) However would rather run this on my notebook (once my notebook is running again- see my other question !) Could you give me some hints as to how to get 3d plots working on the notebook- which other software should I to add to the basic SAGEmath installation? And is there good information available on this?

(and do you recommend jsmol/jmol for mathematics graphics? )

al ( 2018-01-29 19:39:54 +0100 )edit

Ooops, in fact what I want is apparently called "orthographic projection", not isometric ! Any ideas?

al ( 2018-01-29 19:44:36 +0100 )edit

In fact, what I just noticed is that the viewpoint changes as you zoom in. So when you zoom out, say of a cube, it will approach what I want (orthographic projection) as the viewpoint approaches infinity. As you zoom close, you see two nested squares connected by edges, with the back face much smaller as you get close. The problem now is that when I zoom away, the figure itself is getting too small !

al ( 2018-01-29 20:17:59 +0100 )edit

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How can you change the viewpoint of perspective (to infinity) in a 3d plot?

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How can you change the viewpoint of perspective (to infinity) in a 3d plot?