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RHINO TUTORIAL #1
USING RHINO TO BUILD THE RAILING OF A SAILING
SHIP
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This is a basic tutorial on Rhino, explaining
some simple functions and tips to help you :)
The goal is to make a curved, rounded-edged railing that you could
see on a sailing ship, or old fashioned wooden constructions from
forts, bars, fantasy work etc. |
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Basic rules when using Rhino:
1) Make a new layer for every major part of a
project such as "Hull" for a ship's hull; "walls"
for a castle; ""windows" for a car etc. This helps
keep the work space easily managable, as you can hide layers you
don't need to see.
2) Always make a copy of every major part and
curve of an item as you build it, especially before booleaning,
splitting etc. Copy, Paste and Hide this spare. In event of a
problem, you can go back to the copy
3) When starting a new project, open a NEW file
in Rhino so you make sure to select the right scale for your project,
saves lot of hassles if you've chosen "Metres" instead
of accidentally building in "feet" ;) Also, set the
"grid snap" (In "Document Properties") to
what you need for the project, such as "0.1" feet. Beware
of using weird grid snap sizes, such as "0.23 feet",
because it's easy to mess up doing that, rather than stick to
clean decimals or basic fractions.
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#1
The basic goal is to make a railing, starting with
a curve used to describe it's shape around the deck, You use "Solid-->Extrude
Planar Curve" to make this into a solid object, which
I'll will then cut the center out of, to form the railing. To
make the inner cutting part, use "Curve--Offset
curve" and pick a suitable distance inside the rail curve,
use this new curve and again, "Solid--> Extrude
planar curve". We'll use this to "boolean"
the rail (booleans are when you add, remove or blend shapes or
curves out of each other).
Important tips about booleans, they can refuse
to work at times, if one object doesn't poke through the other,
i.e. if surfaces are flush against each other, rather than entering,
they can fail. Also note than in Rhino you can't boolean a simple
surface out of another surface if they don't overlap or touch.
For example, say you wanted to make a glass sphere, with 1 inch
thick walls, you can't just boolean out a sphere from within a
sphere. What you need to do is add some object, or scale a part
so it pokes through the other, such as a thin cylidner boolean-Unioned
into the inner sphere, this new soild can then boolean out the
outer sphere. I know it's odd but it makes sense because spheres,
cubes and the like are simple promitives in Rhino ;) Anyway in
our railing I made the inner cutting object slightly taller than
the surround, to help make sure the boolean works.
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#2
This is going to be the top part of a rail around a ship, comprising
railing, posts that support it, and panels between them. Since
the railing is only meant to be, say 6 inches square, I scale
the railing in one direction to make it thinner. Then I "Fillet"
the edges around the top. Filleting smooths corners, and real
wooden rails folk use don't have sharp edges much (unless you
like getting hurt by splinters, lol)
(yes I cheated, I scaled the object THEN filleted it, to keep
the fillets in proper scale, as if I filleted, then scalled, they'd
have gotten squashed. I screwed up in the #2 picture, so, what
you expect, Picasso? ;) )
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#3
Always check fillets are ok, sometimes they fail and
leave gaps or holes (these can be filled in using the "Patch"
or other commands). very sharp corners fail more than others. Rounded
corners, where you've built the corner using an arc or filleted
curve, have less problems with this because they don't have a sharp
harsh angle, but have many control points and area to work with,
which makes things work better. Usually fillets work fine though. |
#4
I'm going to split the railing into evenly spaced
pieces, because I plan on making this into a 3d model for rendering,
and it's easier to assing textures to multiple items, nealty, rather
than one stretched out railing that will stretch out a texture hugely
and look unrealistic. It also looks more realistic since railings
are not one enormous piece of wood curved right round the bloody
ship, hehe!
To split it evenly, I made a basic surface, using "Surface--->Plane-->Corner
to Corner" it has to be big enough to cut, but not so big
it will overlap through the railing when duplicated. Then I used
"Transform-->Array-->Along Curve"
and selected the starting curve I began with. I chose 12 repeats.
If you're modelling for art rather than engineering, it's good to
use easy to remember numbers for such things, so later on, when,
as in this project, I'm going to making support posts to match the
railings. Twelve splits, and 12 supports will work nicely.
A nice thing about Rhino is you can add notes about
such things to remind yourself later on what you did or plan! Use
the command "Notes", and you can add info and reminders
(bloody handy if you're a forgetful twit like me!) |
#5
Now I've got 12 neatly spaced surfaces, and I use these
to split the rail using the "Split" command.
Tip: don't try and select and do a lots of splits or
booleans at the same time, as it can slow to a crawl or even fail,
better to do 2 at a time or so unless the objects are very simple
like a surface. |
#6
There's a problem, in the display, one of the items
looks weird, it's surfaces only show from the opposite side. This
is because the surface UVs, the "Normals", are inverted.
For non-art-nerds, this means the objects outer skin is one sided
(which is the way most 3d art works), but it's surface is on the
wrong side, like a shirt that's got turned inside out and is invisible
from the outside.
There's several ways to fix this, but int his case I
used the "Explode" command, to break that railing pieces
into all it's individual surfaces, and then used "Join"
to fix them all together, and make Rhino re-calcualte it's surfaces,
and it fixs the UV problem!
Always beware of inverted normals in any modelling program.
In Rhino the "dir" command will show the direction the
surface "normals", if it points inwards (wrongly), use
the "Flip" option inside the Dir command line to fix this. |
#7
Now I've got 12 railings, however, they are "surfaces"
they are not true solid objects, they are just curved tubes in effect.
This isn't a big deal, as they will export and render just fine.
However, if I want to show the railings are solid, say, damaged,
moved etc, I need to close the gaps in the ends, becaus they have
open holes at the ends. It's easy to do, just use the "Solid---Cap
Planar Holes" command.
By the way, capping those objects will add more polygons:
for art rendering, it's always a choice between how many polygons
you'd like, and think you can afford to put into a scene, so it's
up to your choice in such matters. |
| Have fun with Rhino, more tuorials to
follow I hope :) |
BASIC GOLDEN RULES OF RHINO
;)
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#1
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#2
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#3
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#4
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#5
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#6
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#7
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#8
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