CNC and the art department
bY jOHN mANN
The art department is an environment where time is often at a premium. Schedules get juggled, the weather, availability of the talent and script changes are amongst a myriad of factors that often result in seemingly impossible deadlines.The introduction of ever higher definition recording has meant that a hero prop or close up on a scenic feature has to achieve ever higher production values.
CNC milling, scanning and modelling can, when applied to the right tasks be a great help with these conflicting parameters and may at times be a get out of jail card!
3D models can be scans, from people to textures and things, if it will keep still it can be scanned, mobile hand held scanners are battery powered, in competent hands they can quickly capture 3D images, these may be re sized or edited to suit the needs of the moment. If an object or texture cannot be moulded then scanning is a perfect non invasive method of reproduction, being digital, the image may be passed around for comment or approval.
3D models can be sourced from online libraries, just like image libraries, thousands of scans and constructed models are available, some are free and others may be downloaded and used for a fee. They are an amazing resource, everything from scans of museum pieces to models of farm implements are available, they can be adapted re sized and it is easy to see what you are going to get.
3D models can be created in a variety of ways from scratch, Rhino, Blender, CAD and a host of other software packages are now in common use within art departments and mean that unique objects and textures can be originated, tweaked and perfected, scans and models may be incorporated and adapted to produce exactly what is required.
Objects and panels can be machined from a wide variety of materials. Polystyrene is light relatively cheap and comes in a range of densities, it is fast to machine and is particularly useful if it needs to be worked by hand or adapted after machining. Poly is a good material choice for producing large objects, it may easily be bonded to supportive structures and being able to cut it with a hot wire makes it easy to incorporate an armature after it has been machined. It is not suitable for solvent based coatings but is fine with polyurethane, epoxy, plaster etc. (My personal favourite!)
Wood and MDF machine well and are good for resolving fine details, they can be immediately structural and naturally impart all the qualities of grain and weight with few scenic hoops to jump through.
There are a variety of foams in polyurethane, PET etc they can vary in density and hardness from oasis like foam to tooling board, can be handy on aesthetic grounds and particularly for SFX where weight, strength buoyancy etc are needed.
3,5 or full fat 7 axis, dependant on the job and shape of the piece, whichever machine is most appropriate for the job it is programmed to machine the piece by loading the 3D model into the software. Some shapes may need to be digitally broken up and cut as separate elements or cut with a supporting scaffold of material to reduce vibration or protect delicate shapes. Dependant on the shape and size, programming may take anywhere from an hour to a day or more, the software will give an estimation of the machining time and once it starts running it can be left to get on with it with minimal oversight, at need the machine runs 24/7, handy for those emergency situations!
These last few shots show the progress of a piece that we made for a Krypton, a practical and beautiful sofa, 2 weeks from sketch to completion!