For questions about calculating intersections using {tikz-pgf} or {pgfplots}, including PGF's `intersections` library.

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17
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1answer
1k views

Intersection of two surfaces

I'm trying to create a signed distance function S(x), where I want to intersect S(x) = 0 with a plane. The problem is not to get the two functions into a plot, but to get the two functions to visual ...
12
votes
1answer
1k views

Intersections in PGFplots

I can get intersections to work in TikZ, but not PGF plots. I defined a command to show the intersections to make sure that it is identical in both cases. Commenting out the \ShowIntersection line in ...
11
votes
3answers
5k views

TikZ: Intersection of two lines

what is the easiest way to determine the intersection of two lines? I tried \usetikzlibrary{intersections} \begin{tikzpicture}[every node/.style={black,above right}] \draw[name path=line 1] (0,0) -- ...
11
votes
2answers
1k views

Crossing paths in TikZ without intersection

Once again, I'm preparing a new logic puzzle; Resuko to be precise. For the race track, I would like to have a symbolized bridge/underbridge -|-. I searched this site, but only found this question: ...
11
votes
2answers
3k views

Insertion of perpendicular symbol at intersection of two perpendicular lines

This provides good details on How to draw a line passing through a point and perpendicular to another?. What I would like to do is to extend this somehow to add the usual geometry symbol to indicate ...
11
votes
2answers
2k views

Coordinates of intersections

In axis environment I have a curve and a line intersecting it. How can I get components of intersection-1, intersection-2 etc. in axis units? \documentclass{minimal} \usepackage{pgfplots} ...
11
votes
1answer
171 views

Given four nodes forming a quadrilateral, how do I find the node at the intersection of the diagonals [duplicate]

I'm trying to find and name a node at the intersection of the diagonals of a quadrilateral formed by four other nodes. However, I'm not drawing a path. All I can seem to find in the tikz manual are ...
11
votes
1answer
437 views

How to decorate a path with arrows at certain coordinates?

Next example (taken from TiKZ manual) shows how to find intersection points between two paths. Once you know intersection points it's easy to decorate them with any marking. But if I want to use an ...
10
votes
2answers
1k views

“pgf Error: No shape named i-0 is known”, but only upon 2nd run

Update 2012-01-31: This seems to be a version (and/or OS specific) problem. It breaks on my latest TeXLive2011 on a Mac, but I can get it to run on my PC version of MiKTeX 2.8, and @MarcvanDongen ...
10
votes
2answers
1k views

Intersection of 2 surface plots in pgfplots

My question is pretty much a duplicate of this one. I'd like pgfplots to display the intersection between tho surface plots properly. Unfortunately, my function is quite different from the one in the ...
9
votes
2answers
468 views

Tikz — Rotating a line around an intersection

I've been trying to rotate a line around an intersection. The problem (I think) is that the intersection is in a previous scope (I need that to have the correct clipping), and the new scope doesn't ...
9
votes
1answer
175 views

Avoiding line intersection

i wanna do something like that: Non-intersecting lines on class diagram with that: http://www.texample.net/tikz/examples/oxidation-and-reduction/ It will be something like:
9
votes
1answer
349 views

Drawing little semicircle to show that two intersecting lines are not connected [duplicate]

I want my diagram to show that two intersecting lines are not actually connected, but one passes above the other. The best result I would like to achieve would be a small semicircle as used in ...
8
votes
3answers
637 views

Intersection of lines to draw a convex function

I'm trying to draw (in TikZ) a convex function f constructed as the minimum of the linear functions f1, f2, f3 and f4. To do that, my inclination is to use the intersections of said lines to find the ...
8
votes
3answers
1k views

Draw line from a point to another line (along x-axis or y-axis) in TikZ

I would like to make use of the intersection tools to draw a line to another line in a way that it only reaches along the x-axis or y-axis. I mean I currently think that I would achieve this via the ...
7
votes
3answers
656 views

Bad intersection of lines in TikZ

Consider the following: \documentclass{minimal} \usepackage{tikz} \begin{document} \begin{tikzpicture}[line width = 4] \coordinate (a) at (0,0); \coordinate (b) at (1,0); \coordinate (c) at (1,1); ...
7
votes
2answers
246 views

Filling the area under a graph based on intersection with another graph

I'm trying to produce this: But I can't get any further than this: This is my code: \documentclass{minimal} \usepackage{pgfplots} \pgfplotsset{compat=newest} \usetikzlibrary{intersections} ...
7
votes
3answers
2k views

How to Intersect an arc with a line without calculating the angle

I'd like to draw an optics-related figure, for which I need to draw several beams with varying opening angles, which will need to be labeled. What I've come up at the moment (boiled down to a minimal ...
7
votes
2answers
210 views

TikZ: naming paths in a \foreach and accessing them later

\documentclass[convert = false, tikz]{standalone} \usetikzlibrary{calc} \usetikzlibrary{intersections} \begin{document} \begin{tikzpicture} \coordinate (P1) at (60:4cm); \coordinate (P2) at ...
7
votes
1answer
2k views

How to access \xmin, \xmax, \ymin, \ymax from within PGFplots axis environment

In the MWE example below I have the values specified twice, but would prefer not to have to do that. Furthermore, it is possible to allow PGFplots to automatically select these end points so I would ...
7
votes
1answer
335 views

TikZ doesn't find all intersections between plot and a line

Why doesn't TikZ find all intersections. They are obviously there … \documentclass[border=10mm]{standalone} \usepackage{tikz} \usetikzlibrary{intersections} \begin{document} ...
7
votes
1answer
451 views

tikz intersection fails in combination with the library calc

In the second example I am trying to work the the library intersection. It works fine as long as I don't use the calc library. The first example shows my intention. I am using ($2*(w1')$) which ...
7
votes
1answer
384 views

ellipse intersecting a circle

I am trying to draw an ellipse which intersects the sphere of influence, that is, the dashed circle around the moon. The ellipse needs to pass through (-170.864:.7cm) location along the v0 vector and ...
7
votes
1answer
436 views

Is there a way to clear paths previously defined with name path global in TikZ

In the solution to Intersections in PGFplots it was pointed out that each \addplot command was drawn in its own scope and using name path would not survive outside of that \addplot command. The ...
6
votes
1answer
294 views

TikZ Intersection missing the true intersection slightly

I'm having issues with the intersection feature. It works, but it seems to "miss" the true intersection a bit. The code below produces the error for me. See this image (can't post it directly because ...
6
votes
1answer
191 views

Number of intersection points

In this examle from pgfmanual p 132, how to use \t the number of intersections point outside \fill command. I tried \def\Nb{\t} but it dosen't work. \begin{tikzpicture} \clip (-2,-2) rectangle (2,2); ...
6
votes
1answer
157 views

Am I able to intersect curves after rotating?

I would like to intersect arc and sloped line as it's discribed in the code after having rotated the sloped line. Why doesn't the red point belong to sloped line? I hope my question is quite clear for ...
6
votes
1answer
417 views

pgfplots intersection with path

I am trying to find the intersections of a path with plots from pgfplots via the intersection library. The intersections found clearly do not match the visable intersections. It seems as if they are ...
6
votes
1answer
179 views

Calculate the intersection between a path enclosed by a `scope` and another path

I have constructed a circle using the through package. I would like to create a coordinate at the intersection of this circle and another line. Is there a way to do this? I tried to name the path ...
6
votes
1answer
513 views

TikZ: Drawing an ellipse through two points

I am trying to construct a portion of an ellipse that connects point P1 and P2 but I don't know anything about the ellipse besides that F is one of the foci. All I know is that an elliptic arc ...
6
votes
1answer
127 views

Fill from path to axis with tikz intersections

I am trying to represent parts of a plot that extend from a simple curve to the boundaries, but I can't find a simple way of creating the closed path from the intersection of two paths. I have seen ...
6
votes
1answer
400 views

Tikz: placing a node at the intersection of two circles along a hyperbola

I know one can use the intersection package to find the point of intersection but I don't understand how to do it yet. I would like to label the increasing order of the intersections F^*_2, F^*_1, ...
6
votes
1answer
116 views

The intersection of a sphere with planes through an axis tangent to the north pole

I am trying to draw a picture of a very simple sphere - i.e. one big black circle with additionally, an equator indicated with solid line in front, dotted in back. on this sphere I want to draw a ...
5
votes
3answers
178 views

Drawing a segmented circle

I'm trying to draw another larger circle that is also centered at (0,0). In words I'd like to "walk out along the top horizontal arm to its halfway point, then draw a circle all the way around to the ...
5
votes
2answers
363 views

TikZ: How to draw an helicoid and fill area below curve

I am trying to draw an helicoid and to fill the area below the curve. Since the aim of the figure is just to "give an idea", I would prefer to keep it simple and to avoid using PGFplots and GNUplot -- ...
5
votes
2answers
262 views

Highlighting intersections

I would like to highlight the region C in the Euler diagram below. I tried to play around with fill opacity command, but I was not able to highlight C alone. Should I use the intersections libraries ...
5
votes
1answer
195 views

How to find the intersection of two `path3[]`

I'm using Asymptote to draw some figures and I need to put a dot on the intersection of two path3[] but the command intersectionpoint() doesn't work for path3[]. What can I do?
5
votes
2answers
108 views

Sketching conic sections as intersections of cone and plane?

I would have thought this would be trivial, but I still haven't found an easy method. All I want to do is draw a cone, a plane, and their intersection (which will be a conic section). Something ...
5
votes
1answer
1k views

How do I name a plot in tikz and use it for intersections?

I want to create a figure with 3 plots, a vertical reference line, and marks at the intersections of each plot with the reference line. The plots come from an external table. Plotting works, but ...
5
votes
1answer
522 views

Right Angle Symbol Alignment with TikZ/Calc

I used a solution from @Jake from this post Insertion of Perpendicular Symbol at Intersection of Two Lines, but the alignment is not quite right. I have my suspicions why, but I don't understand the ...
4
votes
2answers
231 views

Shading area between curves

I am an old LaTeX user but just beginning to discover PGF and TikZ. I am trying to shade areas between 3 curves and from what I read I could do it with min and max functions, but forwhatever reasons ...
4
votes
2answers
162 views

Tikz: wrong intersection with axis

In the following code the dashed line that intersects with the y-axis is out of place and I don't know where I'm making the mistake (if there is any): \documentclass{article} \usepackage{pgfplots} ...
4
votes
1answer
758 views

Tikz: drawing a line to the edge of a circle

If I wanted to draw a line to the edge of a circle, I could simple do the following \pgfmathsetmacro{\a}{2} \draw (0, 0) circle (\a cm); \draw[-latex] (0, 0) -- ({\a * cos(angle)}, {\a * ...
4
votes
1answer
127 views

Pgfplot second intersection point

As it can be seen in the figure i added a line from the first intersection (y=2x and y=6-x) to x(2). But i couldn't add a line from second intersection (y=x and y=6-x) to x(3). i tried intersection-2 ...
4
votes
1answer
190 views

Plotting the frequency bandwidth

I do not have almost any experience with pgfplot and I am having some problems with something which seemed really easy. What I want to do is filling the area between a function and two vertical ...
4
votes
1answer
539 views

How to specify a name path for the axis in PGFplots

When I use the {axis} environment, the axis are drawn automatically so I am not able to specify a name for them? I would like to be able to compute intersections with the axis as in Intersections in ...
4
votes
1answer
80 views

Why two macros in intersections are not expancded?

Two path names inside intersections are not working. Only one macro seems to work. I have tries all the combinations of macro expansion but in vain. In the following 'h\x and \vy' is not working. It ...
4
votes
1answer
304 views

More: Generalised: Accessing the logic values of a TikZ coordinate

This is a follow-up question to: Generalised: Accessing the logic values of a TikZ coordinate. In that question a PGFplot answer was suggested by jake. I took that answer and modified it to the ...
4
votes
1answer
250 views

Tikz: Drawing a line from a focus to the edge of an ellipse

This question is similar to Tikz: connecting two vectors from the focus of an ellipse to the edge but not the same. In this instance, I want the the length of line to be a specific distance. If ...
4
votes
0answers
814 views

Drawing tri-axial ellipsoid and intersecting it with a sphere [closed]

I would like to draw a tri-axial ellipsoid (that is, an ellipsoid with three different main axes). I'd also like to draw a sphere in the same picture, showing the curves of intersection between the ...