How Did They Do X Special Effect?

Maybe a bit of an odd topic, but I couldn’t find any other thread that fit for this.

I figured this could be a place to discuss any special effects shot(s) in any of the SW movies that for one reason or another can’t be easily solved just by googling it. F.ex. most of the OT effects are so well known and have been discussed for so long that it’s not hard to find a detailed breakdown of almost any effect done for those movies (though I’m sure some do exist), however this isn’t always the case for the PT, ST, etc. So if there’s an effect shot that has been nagging you for a while maybe ask about it here and hopefully someone has a source of info about how it as done or at least we can discuss and theorize as to how it was pulled off.

I’ll start with this:

Does anyone know how they did the melting metal effect when Qui-Gon cuts through the blast-doors at the start of TPM? I could be wrong, but it looks too good to simply be a late 90’s CG effect, so I figured maybe there’s some kind of combination of CG and practical elements. The shots of the door melting from seen from the inside looks very practical, but I couldn’t find any info about this scene at all.

https://youtu.be/eZ2fRsTSF4Q?t=132

Mocata said:

It’s probably CGI? So logically speaking there is no saber prop. To have a physical door melt next to the actor would require some interesting chemical choices. Maybe it’s a miniature they blue screened into the shot in post?

I was thinking the latter; that they melted a prop and then added Liam Neeson in later or just the melting element was added to the shot with Neeson and the door. The way some of the shots are framed though it would make sense that Neeson was added in later. The spark is definitely added in post as the light bouncing off Neeson is way too weak and looks fake (provided you slow down the clip that is).

It could of course be CG, but if so it’s very advanced for the late 90’s. It’s possible they did melt something for real and then used it for reference when animating it.