Tuesday, March 27, 2012

Building Miniatures in Sketchup

I use Sketchup to do my solid modeling.  There are arguably better software packages out there but none are as user-friendly to a beginner as Sketchup. Couple this with the fact that the software is free and you get a wonderful addition to your collection of toys.

First off let’s talk about raw Sketchup.  The virgin version of Sketchup is pretty basic.  You get modeling tools to make basic vector shapes which you can then use the push/pull tool to extrude into basic 3 dimensional objects.  A lot of beginners never get past this point.  Oh.. you can draw a square and then extrude it into a box.  You can use this to make cylinders, squares, rectangles, strait tubes, etc.  The basic forms are essentially linear however.   In order to make a sphere you need to play with the “follow me” tool.  This tool allows you to take a vector shape and drag it along a path to make 3d geometry.  So a circle dragged across a circular path makes a sphere.  But you can also make pipes, a variety of semi-organic shapes this way.  In the paid version of Sketchup you can use a Boolean tools.  These tools take two solid 3d objects and combine them into one.  The Boolean tools are great but the same effects can be achieved by using the Intersect model or Intersect context tools and then erasing the surfaces and boarders you don’t want.

Perhaps the most frustrating thing about Sketchup is that it simply feels like it was meant for making houses.  Its shape tools make it hard to make truly organic shapes without complicated work.  All the tools are based off of lines and there is no way to manipulate faces directly apart from selecting them and using the move or scale tools.   Likewise its scaling is designed for much larger objects.  When working on a miniature I generally build it 1000 times the intended size and scale it down outside of Sketchup.  If I don’t Sketchup tends to lose faces and lines randomly.  For truly organic surfaces such as faces I’ve even started working at 10,000 times scale to insure no loss of fidelity.  But even with these drawbacks Sketchup’s tools are very powerful and its extensibility opens the door on what you can do.

Now the real place Sketchup shines is its plugins.  Sketchup uses an extension language called ruby.  It allows people to write scripts that add functionality to Sketchup.  And a lot of plugins have been written for Sketchup.  There are a large variety of sites that offer plugins both free and paid.  The best in my experience is a site called Sketchucation which offers both free plugins and a large support community.  I personally have somewhere around 50 plugins installed.  They do everything from simplify resizing a model to check if my model is solid.  They are a life saver.  I figured I’d jump in with a few plugins that I use regularly to work on miniatures.

These are presented in no particular order apart from it’s the order I copied the links.

Loop subdivision is a mathematical process that takes a surface and cuts it into smaller and smaller surfaces.  It turns a basic flat surface and makes it an organic rounded surface.  The general shape will remain the same but you lose the sharp edges and valleys in favour of a rounded surface. It’s like tossing things into a rock tumbler, the shape edges get knocked off and the shape smoothed.  It’s good for taking a linear shape and turning it into an organic one when you don’t need to maintain the precision of the shape’s boarder. 

SCF Power Toolbar is one of a collection of toolbars that SCF has made.  They collect a bunch of tools that are helpful into a single interface.  The power toolbar has a bunch of useful tools such as a scaling tool that can deform a shape and a tool that generates piping along lines.  The other toolbars have extensive shape tools, specialized selection tools, and view tools to help you navigate your model easier.

Softening in a model is ignored when you print in 3d so you might not think this tool is that helpful but it can be.  Softening can reduce the number of visible lines on screen helping your software speedup.  Also a softened surface can be selected as one rather than face by face, as a result it can help you when you have surface positioning to do.  Beyond all this it helps give you an idea of how the model will look finalized.

Smart Push/Pull is a plugin that adds functionality to the normal push/pull tool.  Instead of just dragging a surface in or out it allows you to maintain the integrity of adjacent surface effects such as bevelling. As with the regular push pull tool it only works on faces but now it will also extend adjacent faces resulting in a uniform extension of a surface.  This is helpful when you have to alter complex shapes after you’ve assembled them.

Component stringer takes components and arranges them along the facets of a line.  This allows you to build a shape and the arrange copies of it along a pre-constructed line.  The caviate is that it works best with lines made up of equal length segments. It allows you to make intricate cabling, chains, and similar structures made of repeated shapes.

This tool is used to take a shape and bend it along a curve.  You have to define the curve you want and it bends the shape to match the facets of the curve.  It has some minor issues with recurved surfaces but for the most part is quite effective.  The surface is essentially subdivided along each facet and then tilted by the degree of the facet before being reconstructed.  When working at small scales this process loses a lot of faces resulting in a lot of holes to fix.  Even at large scales it can give you some problems resulting in some geometry being lost.  Over all it is a great tool once you get a handle on how it works.

This is a tool which allows you to pull an entire surface.  This extrudes the same so it has thickness.  You can choose to pull the face, the joints, or the vectors each having a slightly different result.  It pulls everything along the vector of the surface’s centre making it a uniform pull.  It creates complex geometry however and as such isn’t suitable for basic push/pull operations.  It’s also of note that it acts on the surface you select so the original surface will be gone if you don’t duplicate it before starting the pull.  While this offers a lot of versatility in pulling surfaces it requires a lot of clean up after being used.

This is a toolbar that adds several tools that allow you to draw on a surface.  This is of particular use when trying to add detail to organic shapes.  The tools can seem buggy because they are affected by the existing geometry they are drawn on.  However they work well to design surface detail before using joint push pull to extrude them.

Round corner takes a selected line and bevels it to produce a smooth rounded edge.  It’s good to use on sharp corners to make a consistent surface that looks professionally machined.  I’m fonder of using flattened surfaces than rounded ones but this tool has both options.  It can cause some errors when you have complex surfaces such as those that have double curves.  But over all the geometry it creates is more consistent than you can produce by hand.

Curviloft is a tool that can take a group of lines and generate a face for them.  The resulting face blends the shapes together morphing the surface to make the best geometry it can.  Curviloft is sometimes finicky about the way it operates but overall it makes good surfaces that can really help you out in a pinch.

Like curviloft blend takes lines and builds faces. Unlike curviloft blend builds non-uniform organic shapes using curved lines.  The caveat is that the lines need the same number of segments.  You’ll end up with more bulbous shapes than curviloft’s smooth transitional surfaces.  This can be helpful when making strange organic shapes.

Shell is pretty useless when you are trying to shell a model that has any sort of under cuts.  However it is good at taking a selected surface and making a scaled surface a set distance away from it.  For example you could make an organic shape using blend and then run shell on that surface making two parallel planes.  Then a quick selection of the bounding lines and a run of curviloft will make an organic solid object of a uniform thickness such as a banner or cloth hanging etc.  Fun huh.

Fix solid is a tool which attempts to automate the process of repairing models.  It searches through a model and finds open gaps, stray lines, and such and removes or fills them.  It doesn’t work well with complex high poly models but it works great for simpler models.  I use fix solid before trying to manually repair anything.  While it doesn’t work well for my big organic models 9 out of 10 tries fixes the small parts.

If fix solid fails solid inspector is the next step.  It allows you to highlight and zoom to solid errors in your model.  Just open the instance of the model, run solid inspector and press enter. Bam takes you strait to the problems.  It helps you find problems and fix them before export.  If you get no other plugin solid inspector is basically required, unless you want to manually hunt down ever manifold error and gap in your model.

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