Just released the effect here: http://www.scirra.com/forum/effect-alpha-threshold_topic57568.html

You can check the updated demo with the fire effect included below:

Alpha Threshold Demo

Finally got the time to release this.

Description

Alpha values below the threshold are converted to transparent and above to opaque with a smoothness control.

It's useful to simulate metaballs when applied to a transparent layer and get fluid-like effects. When combined with physics can simulate a pseudo liquid, and with particles can simulate fire.

Parameters

Threshold: Alpha threshold from 0 to 100. Controls where to put the edge based on the opacity value.

Smoothness: Controls the smoothness of the edge.

Flat Colors: Set to 1 to unpremultiply the colors and make them flat. 0 preserves the black shading caused by premultiply.

<img src="https://dl.dropbox.com/u/7871870/construct/Effects/alpha%20threshold/prr-alpha-threshold.gif" border="0">

View Demo

Downloads

Download Effect

Download Demo capx

How to Install

Just drop the two files under your "Construct2/Effects/" folder.

The 2D map seems just like a level editor, I think the runtime read their positions and create 3d objects accordingly later.

I think adding a percentage parameter with a 'lock aspect ratio' would solve it quite well:

<img src="https://dl.dropbox.com/u/7871870/construct/image-resize-01.png" border="0" />