Part two of four blog posts outlining the production of a 3D model (or scene) from pre-production to final rendering.
After the model has been completed, it’s time to move onto the more technical elements.
UV Mapping -(aka, the tedious part)
UV mapping is the process in which the artist -or program- unwraps the model from a 3D shape (with three co-ordinates, x,y and z) to a 2D map (using u and v co-ordinates). When done manually this generally involves selecting a number of faces and creating a planar map, which can then be edited to best fit the model and the eventual texture.
It’s important to keep the map as clean and efficient as possible so as to provide the best possible base for texturing – this can be done by mapping parts able to be duplicated, or mirrored in the same place (to share textures and save space), ensuring that seams are both kept to a minimum, and strategically placed, and giving less room to small and/or hidden parts of the mesh.
After completing the jigsaw puzzle that is UV mapping, it’s time to move onto the texturing stage. Texturing can be done in one of two ways – either through a shader based system within the 3D program (though there are some interesting shader programs being developed) or by painting directly over the UV map in a graphics program – usually Adobe Photoshop.
Both methods have their advantages and disadvantages and it’s best to choose one that will suit what the model will eventually be used for – for example, texturing straight onto the UV map is generally used for game models, as this preserves processing power.
The word rigging brings to mind ship’s rigging, and in the end, the process is really not so different. Rigging in 3D models refers to assigning the characters bones, and joints in order to allow it to move (something that is needed in order to animate the model). In its simplest form this allows basic models to move – for example, the hinge on the chest being made in class – but this quickly becomes more complex when the joint needs to bend without overlapping, or whether the model needs to be able to deform.
Generally speaking, the principles of animation are the same for 3D animation as they are for old school 2D animation – the only thing that differs in in the way that the actual animation process is executed. Once the model has been fully rigged, the artist can then use the keyframing feature in their 3D software to animate it from pose to pose, allowing the software to fill in the gaps. These can later be tweaked (as automation rarely provides perfect results!) through the use of the curve editor – to allow easing in and easing out.
CardKingdomGame.com, J. (2012, April 24). Character Pipeline 5: UV Mapping for Artists | Card Kingdom. Retrieved from http://www.cardkingdomgame.com/2012/04/24/character-pipeline-5-uv-mapping-for-artists/
Fejer, K. (2011, January 4). An example of both a finished textured model and its texture map – by Kenneth Fejer at kennethfejer.deviantart.com [3D model and Texture Map]. Retrieved from http://kennethfejer.deviantart.com/art/Lowpoly-Biplane-192073358?q=favby%3Aaeliaa%2F11137816&qo=6
Making Of Big Hero 6 – Animation, VFX [Video file]. (n.d.). Retrieved from http://www.itsartmag.com/features/making-of-big-hero-6/
Slick, J. (2014). What is Rigging? – Preparing a 3D Model For Animation. Retrieved from http://3d.about.com/od/Creating-3D-The-CG-Pipeline/a/What-Is-Rigging.htm