Hi Arno and all,
Here is yet another request for FXE; an automatic check to see that when entering values the second is greater than the first. I've done the opposite twice now! P3D v2 gives a cryptic error message on startup saying something like 2.0000043030003 is greater than 1.000205550505. And then of course I can't remember all I had done recently.
I've made two kinds of silly mistakes. One was not noticing the minus sign while tweaking an entry. So [-1.00, -2.00] will not work. Color rate can be confusing to me too. It's the fractional time that the particle is colored the start color, then the end color, but there are two ways to interpret this; if say you put 0.2 for the last value, it does not mean that the last twenty percent of the time the particle is colored the end color. It means that at the 20% time mark, the particle assumes the end color. So a color rate of [0.2, 0.1] will not work and P3D v2 (and perhaps FSX and v1?) give an error message. Fade In and Fade Out work the same way. An automatic check for these errors would be handy as they can be hard to spot quickly if there are lot's of emitters.
Speaking of color start, end and color rate, has anyone figured out how to make an effect slowly and completely fade out? This would avoid the stuttering effect that can be more or less obvious depending on the effect. One would think that simply setting the alpha value in the End Color to zero, as is done in many of the stock effects would work, but it seems not to. I did find what appears to be an explanation in the SDKs of FSX and P3D. Although it's rather hidden, under 'Color Start Red, Green, Blue, Alpha I find this:
The initial color of a particle. Use the color dialog, or input the values directly.
The alpha value here applies throughout. The alpha value in the XML file for Color End is ignored.
Funny that a description of how the End Color works is found in the Start Color section.

And tweaking this value in FXE seems to reflect the above; I don't notice any change.
This might be more complicated, but it would also be very handy to be able to toggle an opaque surface in the xy plane to simulate the ground or water surface. I'm experimenting with wake effects that rise and then fall, all the time being normal to the surface but it's currently hard to see what the effect will look like in the sim.
I'm interested in this now because in solving some of the problems with effects in P3D version 2 (like the floatplane wake effect being referenced to the model datum and wake effects on boats not showing) I finally decided to try to fix up the what to me are very outdated stock effects. Compared to the current standards some like the wake and spray effects look quite crude to my eye. Even the wonderful new Aerosoft Twin Otter Extended has these issues. If anyone else out there is interested this topic, I hope they might post or send me a pm.
Larry