Home of Professional Cinematography since 1996

Molten Metal Effect

>I will be shooting a scene for a commercial that depicts molten metal being removed from a furnace and poured into a mold. It is probably impractical to stage and shoot in a working foundry as this has to dovetail into other production requirements. I am considering the effects route and will shoot some tests; either pouring an ultimatte or scotchlite paint and supplementing with roto-work. The foreground would be worked with effect lighting to suggest the glow coming from the flowing liquid metal. Anyone have any suggestions on this?


>Hi Joseph,

>I recall an article in Cinefex mag a while back (sorry for the lack of exact date & issue) for that volcano movie. It had extensive description of how they recreated the look and flow of lava, which was made by a combination of physical materials and UV light that made for a very convincing look (and it was scale on top of that). I remember them saying that they 'pioneered' the study and development of molten rock effects outside of the CG department. Most of what they were doing could easily be replicated by a good effects team and your lighting.

>If memory serves correct - it may have been the 'Contact' issue.

>Jeremy 'something or other' Benning


Joseph,

>I was one of the D.P.'s for the above mentioned Lava effect. Read the article in Cinefex number 71 (that's the Spawn (on cover)/Contact/Volcano/Batman and Robin issue) and I will be happy to answer any questions about the shooting. One limitation we had that you might want to know about. The flow always looked best at 4 FPS - always. Good luck,

>Eric


>Explain scotchlite paint for us. Does this exist ?

>Methyl cellulose (spelling ?) with a UV sensitive pigment excited by UV lights makes a glow (as I think was the case with the "Volcano" effects).

>Mark Doering-Powell


> Explain scotchlite paint for us. Does this exist ?

>It does indeed - in fact you can buy it (or could buy it) in LA from a sign-painter supply shop in downtown LA called Logan or something like that. The paint is basically a suspension of glass spheres in white paint and should be mixed VERY well for a very long time before using


>Scotchlite does still exist. In the NY area there are several industrial road sign companies that stock quantity. And it's available in basic colors. White, green, blue, etc.. While it does reflect light (glass spheres) it is not as reflective as Scotchlite material. P Weiss


>It's used on nearly every highway in the US, all those reflective center lines, etc. Wade Ramsey, DP


>Hi Joe:

>One of our principals, Mat Beck, was the visual effects supervisor on "Volcano" - we made lava for a year on that production!

>"Volcano" lava was either practical or CG, depending on the shot called for. Mat typically stuck with a philosophy of using practical lava wherever possible due to the self - rendering complexity of a natural compound. The compound contained phosphors and was illuminated by a large amount of conventional and UV light - almost like the UV MoCo - matte passes done awhile back.

>We opted for CG lava as direction became more complex and outside the odds of a good take using practical. For instance, tracking the element to a vehicle, having it emit plumes and sparks, a wide shot of it snaking down the street, etc.

>We'd have to know a more about your spot to propose one over the other. Lava is an organic element and in such respects, must be designed in lieu of the specific shot you're attempting. Maybe your direction is complicated and so under the above a CG approach would be pertinent - however maybe not the case if there are complex fluid dynamics involved which challenge the realism attained using today's 3D rendering engines.

>Let us know if we can help.

>Best regards,

>Ryan (Thompson),


>You may already be aware but, if you use the scotchlite paint - be sure to consider the lighting spec. Scotchlite is designed to have a considerable and logarithmic falloff and so you would need to light up your compound from every angle. Maybe phosphor or CG would be better.

>Ry


>Actually, the only place you want to light the various scotchlite products is precisely from the camera's taking angle...We usually put a pane of glass in front of the lens at a 45 degree and pop a small light into it to make the scotchlite do it's retro-reflective thing. (Same principle as a teleprompter) mark


>