OnnovanBraam - Spline Modeling

8/13/2019 OnnovanBraam - Spline Modeling

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Welcome to this introductory tutorial about splines! Splines are a powerful

modeling tool, which has it's pro's and con's, but for me until now, I have found

mainly pro's. Modeling with splines is very different from box/polymodeling, but

in the end the results will be much alike.

The Basics

I'll start right away with showing you the absolute basics, that will come back all

the time when you start using splines. So fire up 3D Max, go to the Create Panel

> Shapes > Splines > Line. Click the Line button. You now get some options in

the panel: Rendering, Interpolation, Creation Method and Keyboard Entry. If

everything is ok, then Creation Method should be rolled out. Set Inital and Drag

type both to corner.

Now go the front viewport and draw a hexagon (a six sided 'circle'), by clicking

where you want each point, and connect the last (the 6thwith the first again) and

when the pop-up with 'Close Spline' comes, click Yes. Your result should look

something like so, it doesn't matter if yours isn't exactly the same as long as it

resembles it and has six points:


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Alrighty, now go to the modify panel. You see it's called Line01 and that the

object is of the type 'Line', and has a small 'add sign' before it, this means that it

has multiple sub-objects (just as with editable polies, they

have Vertex,Edge,Face,PolyandElementsub-object...). Click the 'add sign'

before Line and see that Splines have the following sub-

objects: Vertex, Segmentand Spline.Click Vertex to go into the vertex sub-object, you see a small button lights up in

the modify panel (under Selection), this button is the exact same thing as the one

you clicked just now, these let you go in to specific sub-objects. You also see that

the vertices of your hexagon are shown, with one square one. That's your initial

vertex, the one where you started drawing the hexagon. Move some vertices

around and you'll see that it behaves normally, the lines that go from vertex to

vertex move along, so nothing spectacular.

Click the second sub-object (Segment) and you see that your vertices changed

from small crosses to different small crosses! ;) You can still recognize the initial

vertex, is has again a small square around it. The segment sub-object and one

step 'larger' than vertex. It can be compared with the edge sub-object in editable

polies. When vertices have dimension 0, edges/segments have dimension 1.

Select a segment and move it around, you see that again it behaves natural.

The last sub-object, is Spline, go in it (nothing changes in comparison to the

Segment sub-object (maybe your selection is gone), again the same diagonal

crosses for vertices) and select something, you see that the entire hexagon is

selected. So this is the largest sub-object, entire splines can be selected, nothing

smaller. You'll see later on, why this can be handy. For now go back to the vertex

sub-object.

PS: Tip: To go in and out of the sub-object of an object (Spline or Editable

Mesh/Poly) use Ctrl + B, to cycle through the different sub-objects, use Insert.


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Now pan down the modifier panel to the 'Geometry' roll-out. The options here

are all essential to spline modeling, stuff like Create Line, Attach, Weld and

Refine are used ALL the time. We'll start with Create

Line.

Click Create Line (make sure you're in the vertex sub-

object), and now you can draw new lines, but that arepart of the original spline, so you still have one object. So for instace, draw a

rectangle inside the hexagon. It may be that it doesn't become entirely square

when you click 'Close Spline > Yes' again, but we won't worry about that until

later. But what if you don't want to close the spline all the time? What if you

wanted to make a U-shaped line? Ah, yes, that's easy, just right-click when you

want to end drawing a (new) line. Try to make one, this time inside the rectangle.

Right click to go out of the 'Create Line' mode, go into Spline sub-object, and

select the hexagon, then the rectangle and then the U-shape, you see how it

works? You have created three new splines, but they are part of the same object

(Line01). Now remove the last two mentioned, by selecting the rectangle and the

U-shape and hitting delete.

Back in the vertex sub-object, click Refine and move over a segment of your

hexagon, you see that the cursor changes from the original arrow to a cross with

two lines above it, one with an extra dot. Refine adds vertices to existing

segments! So try to break the top and bottom segment (in VERTEX sub-object!!)

into two parts, by adding a vertex in each of them.


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This is very handy for adding detail to an existing spline model and something

you'll be useing intensely once grabbed by the power of spline modeling. Right

click to go out of the Refine-mode.I'll explain something new one, that you may not have thought was important, but

it is! If you already undertsand how it works, then you can skip this part: Snap.

Snap let's the cursor snap to something you want, for instance vertices or grid

points. This may be handy when you want to draw/make

something that certain measures, or when you want something to

line up with an existing object.Press 's' to turn snap on (you

should see a button turn on and off somewhere in the UI (user

interface) when you press it). As default it snaps to grid points,

but we don't want that, so right click the snap button to bring up the Grid and

Snap Settings, click the Vertex radio button to turn it ON and click the GridPoints radio button, to turn that one OFF. Move your cursor over the vertices and

see how it 'snaps' to those points and a small cross turns up when you are around

one.

Okay, now click 'Create Line' again, and draw a line between the two vertices

you just created, with snap turned on. If snapped isn't turned on, then you won't

draw a line that goes from one vertex to another (which is required later on), but

a line that is in the vincinity of those two. And in three dimensions it is

absolutely imperative to use snap, or otherwise it's impossible to draw a line from

one vertex to another... Believe me.

Okay, now refine the newly created segment and draw a line from the most leftvertex to the middle of the new segment (where you just made a new vertex) and

on to the most right vertex. We are taking this up another notch! :)


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As said, snap is important. The new vertices that you draw will come at the

EXACT same spot as the ones you are trying to snap them to. This does not

mean that you can't distinguish them anymore, you can still select them both, but

they need to be at the same place to form a whole.

Vertex Types

Up until now, we have only used Corner vertices (we set that in the complete

beginning, remember?). But this way only very square objects could be created.

So naturally there's more, there are three other types:

Smooth: Non-adjustable vertices that create smooth continuous curves. The

curvature at a smooth vertex is determined by the spacing of adjacent vertices.

Corner: Non-adjustable vertices that create sharp corners.

Bezier: Adjustable vertex with locked continuous tangent handles that create a

smooth curve. The curvature at the vertex is set by the direction and magnitudeof the tangent handles.

Bezier Corner: Adjustable vertex with discontinuous tangent handles that create

a sharp corner. The curvature of the segment as it leaves the corner is set by the

direction and magnitude of the tangent handles.

One of the things that probably isn't clear when you read this are 'tangent

handles'. These are helpers that you can move around to set the angle of the

corner around a vertex. I'll explain some more, with the spline we have made

until now.

Go into the vertex sub-object, select the upper left and upper right vertices, hover

over one with your mouse until it becomes a cross (the one for moving or

selecting, it doesn't matter, as long as you're on one of them) then right click to

bring up the Quad Menu. In the upper left corner you see the four different

Vertex Types, click 'Smooth'. You can see how your spline has changed, it's

smooth around the two vertices you are selecting! Move them down a bit to


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smooth out the line some more, so that it goes through the middle vertex without

a discontinuity of the derivative.

Now select the lower left and lower right vertices, right click one of them, set

Vertex Type to Bezier. Now try to move the bezier handles (the orange lines withsquares at the end), by moving the squares and see how your splines reacts to it,

it tries to keep it smooth no matter what you do: in the vertex the derivative is

continuous. This is exactly what it said in the description: 'continuous tangent'.

See if you can make something similar to the shape I made below, it's not hard,

but if you can make it match this, then you could make it match (almost) any

shape you want.

Select the most right vertices (there are two, but you can only see one, because

they're snapped) and set the type to 'Bezier Corner'. This time the bezier handlesare there again, but the shape hasn't changed and it's not continuous either. Once

more exactly as in the description of this type of vertex: 'discontinuous tangents'.

Move each of the three handles around and see what it does with the shape of the

spline. This type of vertex I use the most: you can create smooth surfaces that

end in a 'square' form, you are in control most with this type of vertex, you could

even make it continuous if you wanted it, but also square, this one has it all. It


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takes effort to get exactly how you want it, but at the end this ones the most

powerfull. Yet still, sometimes you don't even need it, for instance when making

very smooth objects...

Now that you know the basics and the vertex types, try to fool around, make

some trial spline cages, see how it reacts when you make all the vertices of the

Smooth or Bezier type, try to understand why it behaves the way it does, because

if you do, then and only will you be in control to make whatever you can

imagine!

I haven't mentioned the surface modifier yet, but I'll shortly go into what it does

and how to use it. The surface modifier is your tool to make something out of

you spline cage. Once you have the cage, then apply the modifier and voila, one

surface! But there are rules that you have to attend to, to make the surfacemodifier work the way it should: 'Make sure that the Spline vertices form valid

three-sided or four-sided polygons. Vertices on splines that cross one another

should be coincident'. Look in the help file that ships with 3D Max under 'surface

modifier', you'll find all the information you need there. Again, fool around with

different settings for the Surface Modifier, try different Patch Topology Steps,

maybe add an additional MeshSmooth... Trial and error is the way.

Before continuing, check these links:

http://www.comet-cartoons.com/3ddocs/facialmodeling/modeling.html

http://www.cyberkreations.com/kreationsedge/tut/splines/cage.htm

Then you can proceed with this tutorial :)
http://www.comet-cartoons.com/toons/3ddocs/facialmodeling/modeling.htmlhttp://www.comet-cartoons.com/toons/3ddocs/facialmodeling/modeling.htmlhttp://www.cyberkreations.com/kreationsedge/tut/splines/cage.htmhttp://www.cyberkreations.com/kreationsedge/tut/splines/cage.htmhttp://www.cyberkreations.com/kreationsedge/tut/splines/cage.htmhttp://www.comet-cartoons.com/toons/3ddocs/facialmodeling/modeling.html


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First take the blueprints, crop them in Photoshop and place them on planes (for a

tutorial see:here)

Now start drawing splines along the edges of the car in the front view (or side,

just the view where you see the side of the car). I assume you know how to draw

splines and how use the sub-object qua vertices (bezier, bezier corner, smoothand corner). If not then look in the Help file that ships with Max. Make sure that

you always form triangles or preferably squares, never make a 'face' with five

vertices, because it will not work then (the surface modifier that is).
http://onnovanbraam.com/%5bMODREWRITE%5dtutorials/bpsetup/http://onnovanbraam.com/%5bMODREWRITE%5dtutorials/bpsetup/http://onnovanbraam.com/%5bMODREWRITE%5dtutorials/bpsetup/http://onnovanbraam.com/%5bMODREWRITE%5dtutorials/bpsetup/


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Next is placing all the vertices of your spline at the right place in the last and

third dimension. Do that by using the top view: align all the vertices at the right

spot. From here on it is pretty straight forward: do this for all the different parts

(front / rear bumper, roof, hood etc.) Make use of the great tool called snap (seeHelp file for more info). When you did that, add a surface modifier to your

spline(s) and you have a perfect mesh, try to play around with the segments

number and see what happens. An extra meshsmooth always helps too for a final

touch.

The rest of the images is the progress of the scene I used (my favorite car: The

Lancia Delta Integrale Evoluzione).


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And here the final result:


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OnnovanBraam - Spline Modeling

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