The Documents of Stage Hands

Dynamically Additive Geometry for Sculpting in Blender

So how do we use NGons and BMesh in Blender?

SHFortunately, if you are using a version of Blender greater than 2.62 this is not something you really need to be too concerned about. As BMesh was intended to replace the old mesh system, Blender versions greater than and including 2.63 will use it by default, this means that geometry can consist of triangles, quadrangles, ngons or combinations of any type. All you need to do is simply use Blender’s extensive set of polygon modelling tools to create which ever type of polygon you desire and let Blender figure out the rest. The only time you need to be aware of which mesh system you are using is if you wish to import a model created with the new BMesh system into a version of Blender older than 2.63, in that case your model might need to be quadrangulated or triangulated then in the File menu choose “Save As…” and make sure the “Legacy Mesh Format” option is checked before saving.

Dyntopo

Dyntopo is possibly a portmanteau for Dynamic Topology and might allude to a paradoxical (and even whimsical) remark regarding a new approach to constructing a models geometry that comprises it’s topology, as topology typically relates to the properties of objects that are preserved under deformation, a dynamic approach to topology fundamentally implies re-addressing these constructs. As a result it’s worth noting that preservation of geometry components is not an objective when working with Dyntopo in fact the opposite is true. In order to create meshes that deform predictably for animation or other such circumstances from a mesh that was created using Dyntopo, the mesh should first be retopologized.

So How Does Dyntopo Work

Once in Blender switch to “Sculpt Mode”, then in the “Options” Panel of the Tool Menu (which can be toggled on and off by hitting “t” on your keyboard) click the button labelled “Enable Dynamic” or "Enable Dyntopo" (depending on which version of Blender you are using).

The “Multires Modifier” does not work with Dyntopo as the amount of vertices comprising your geometry is controlled directly by sculpting. However, the multires modifier can be utilized when applied to a retopologized model created from a Dyntopo sculpt, followed by a shrinkwrap modifier targeted to the very dense Dyntopo sculpted model. Dyntopo works efficiently with Blender’s ability to hide geometry while sculpting. This can drastically improve Blender’s performance; as with the “Enable Dynamic” option activated each stroke can potentially increase your model’s polygon count. Like many professional 3D content creation suites Blender is not necessarily designed to render vast amounts of polygons in the viewport, so it’s definitely worth keeping an eye on your model’s polycount as you sculpt and to be aware of what your system can handle.