My question is related to this discussion on "querying events"

http://www.mapleprimes.com/questions/125273-Dsolve-Events-How-To-Control-For-A-Sign-Change#comment125426

I thought I might start a new thread.

The following loop is an illustration of the sort of thing I'd like to do with dsolve and events: I loop over a parameter of the "event" and extract information on the solution at different values of the parameter. Here is the code (successfully tested on Maple 15 / Standard / Windows)...

I have a system of 3 ODEs in 3 variables x(t),y(t),z(t) to be solved numerically. I would like to set up events to halt integration as soon as one of the derivatives changes sign.

I've tried things like:

'events' = [ [ diff(x(t),t) >0, 'halt'] ] :

'events' = [ [ diff(x(t),t) = 0 .. 0.1, 'halt'] ] :

I might have tried something like increasing(x(t)) (how nice and intuitive), but if I understand correctly the help page on this, increasing(x(t)...

I'm running simulations in which I produce many plots at once, the purpose being to compare differences as parameters are changed. I'd also like to use some of these plots for publication. I've had problems getting good-looking 3d plots. Here's a strange thing I noticed.

Export the graph by mouse-clicking, export to bitmap:

EDIT : IMAGE POSTED IN MY COMMENT BELOW

Export the garph by executing a plotsetup('bmp') command.

I'm looking for information on the x3d format, with a view to converting x3d to 3d-pdf.

1. x3d formats are available from standard gui by right-clicking to "export".  How can you use plotsetup to access the "Extensible 3D" format with a line of code?
2. what x3d viewer do you recommend?
3. do you have any tips on converting x3d to pdf?

Let me elaborate to provide context to my questions. In a previous post (

The problem has been discussed in mapleprimes before, but I have not come across a neat solution. Perhaps there is one. What is the state of the art for exporting 3D graphics (plot3d, etc.) with Maple 15?

What I think I know is this: standard GUI has a completely new way of treating 2D graphics but has an outdated way of rendering 3D, while the classic GUI, though no longer developed, for some reason typically renders better 3D graphics.

I used to export graphics...