Solid drawing
This principle is about making sure that forms feel like they are in a 3-dimensional phase, showing weight, volume and balance. Being able to draw a figure from all angles makes animating a lot easier. For example, when drawing a line over a sphere, the lines are to follow the contours of the sphere rather than just straight lines. While straight lines drawn over the sphere shows 2- dimensional representation of dividing a circle and makes it look flat, the lines following the contours would indicate depth and volume that the sphere supposedly has. Similarly, when drawing a cube or a cuboid, it is advised to be drawn in a certain angle with a vanishing point and not just parallel lines which will make the figure look flat.
When 2-d animation was all the rage, the trick to make solid drawing apparent used to be to draw characters using solid shapes like spheres, cubes and cylinders, instead of flat circles, squares and lines. To construct characters made with solid shapes meant that the animators had to be mindful of making the character have believable volume and weight. So when showing that the character is moving away or walking towards the camera, it should be drawn smaller or larger appropriately showing the same volume without any displacement. This could be done only by laying out perspective lines to keep track of the distance that the character travels.
Solid drawing also covers the aspect of making the character look realistic. The clothes on a person’s body are never symmetrical. If a shirt is drawn on a character, the animator should try to make the shirt uneven.
Sometimes in animation is it preached that twinning is evil. We’ll leave that up for you to decide, but there are instances where it has the potential to help the scene you’re trying to create. For instance, symmetrical movements often have raw power to them which non-twinned motions might not. If someone slams their fists down in fury on a desk, chances are pretty good they aren’t going to slam one fist down followed by the other. This action might be better suited to simultaneous, mirrored action.