Page 75 - 3D World - October 2017

TuTorials
Master Extrude

WhEn to usE cAps ExtrudinG n-Gons
01When starting to extrude with a simple polygon, always think 02 There is a reason that when creating a disc most 3D software
about if caps are needed or not. A cap is a copy of the polygon that gives a mesh with quads and triangles rather than one single
is being extruded, and which fills the hole at the end of the new polygon. While using n-gons as the basis of an extrude is perfectly
extruded shape. It may seem logical to add a cap if a solid object is viable in most 3D software, there are caveats. For example, when
being made, but this isn’t always the case especially if the mesh is to subdividing a mesh to make it smoother, extruded n-gons can
needs to be subdivided later in the modelling process. Make sure provide unpredictable results. Try and divide any mesh that is to be
that you check the attributes or properties of the tool to see how caps extruded into a topology pattern that can deform sympathetically
can be added. later in the modelling process.

BEWArE of douBlE Extrusions
When starting out in 3D, or even if you are an expert, it can be
easy to hit a tool by mistake and create an unwanted result. This
can be a real problem with the extrude tool, as a double extrude
can create practically invisible polygons which can cause a
mesh to act oddly later in the development process. Thankfully
most 3D software highlights double extrusions by showing a
thicker line where the problem areas are, which is really useful for
troubleshooting a mesh.

ExtrudE Groups EdGE Extrusion
03There is a distinction between some 3D applications about 04 Edge extrusion is a great way to create complex shell meshes
how individual polygons are extruded. While all software will extrude really quickly. Unless there is a specific reason, do not extrude an
a single polygon and associated edge loops, some software can edge from an already solid shape as this can create a single-sided
extrude the selected polygons as individual extruded elements with polygon which can behave unpredictably in a render or if it is being
their own walls. This can be useful, for example, when extruding exported to another 3D program. To start using edge extrudes, work
fingers. It is best to use this kind of extrude with a scale option as from a single-sided polygon and work out from there how to best
otherwise the walls of the extrudes could create conflicts later in the form the topology. Most 3D software can allow you to snap to an
modelling process. existing mesh to help guide the desired shape.

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