The technique depends entirely on the shot and may involve tracking, blend modes, overlay, roto, and Photoshop to paint the overlays. There is no plugin that will do this automatically. Precisely describe or show us the shot for more specific instructions.
I would for sure use tracking and blend modes. But the problem is that I don´t know where/how to start (haven´t even shot the footage yet). But I´m thinking about shooting with a slider, a sideways pan so to speak. That would of course require tracking, no prob. But again, how would I start after I´ve shot the footage? :-)
If you are asking how to do the matte paintings of fire damage to overlay on your footage then you will have to go to Photoshop and add a layer, then start painting. I can't tell you how to do that with a plug-in or effect because you'll need to create the image with a brush or by taking images of fire damage and extracting the burned parts. For example, if you have a door frame that you want to look like a burned piece of wood then you could fine a photo of a burned piece of wood and overlay that image in your photo then crop, clone, distort and scale it to get it to look the way you want it to look. If you have a wall that you want to have burn and smoke patterns on it, peeing wallpaper or blistered paint then if you don't have the skills to draw or paint those in you have to find an image that is close to your original in size and scale and cut out the part you want to overlay and add it to the scene. These overlays just have to be big enough to cover the original footage if the camera moves. A trucking shot (left to right camera move) is easier to work with than a pan because of perspective changes, and a Pan and Zoom is even more difficult.
For example you could take this image:
And combine it in Photoshop with a still frame from your video like this using scaling, stretching, masking to get this:
You could even use similar techniques entirely in After Effects. Like I said, what you use depends entirely on the shot you have and what you want to do. I just took the portion of the wall right of the door frame down to the light switch, scaled it and masked it to fit the part of the wall with the damage, then changed the blend mode to Multiply.
Okay, thanks again Rick!
I´ll give it a go; the challenge here is I guess to get the tracking right. :-)