plotting - Force VectorPlot3D to show One arrow

I am plotting a curl, and I only want VectorPlot3D to show one arrow, I have tried adjusting VectorPoints-> 1, but the plot show's no arrows at all. Is 2 the minimum VectorPoints I can have?

If I cannot make use of VectorPlot3d in this way, how can I use the Arrow function to point in the direction of a vector field at a certain point?

Thank-you

Answer

I don't think it's possible. I assume the vector scaling routine needs at least two vectors. You can fake it though:

VectorPlot3D[{x, y, z}, {x, -1, 1}, {y, -1, 1}, {z, -1, 1}, 
 VectorPoints -> {0.9999999 {0.5, 0.5, 0.5}, {0.5, 0.5, 0.5}}]

Mathematica graphics

Comments

plotting - Plot 4D data with color as 4th dimension

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I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1....

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