Spline Head Modelling part 1

Forward to part 2 | Go to part 3 | Go to part 4 |  Go to part 5 (comming soon) 

Written by Conny Klasson, november 2003, any comments are welcome.

First we need reference images. 
A front and left view will do.

Create two materials and set the diffuse map as bitmap and assign the images.

 

Reference images from Andrew Loomis Anatomy Books  at www.fineart.sk
Create two Plane objects. Make sure that the plane's size matches the size of the bitmap. In this case th btmaps are 102x115 pixels. Arrange the planes in a 90 degree fasion.
Finally apply the materials to the plane objects.

 

First a quick lesson in basic spline modelling. Spline vertices can only be attaced to one or two spline segments. To get three or more segments to meet at the same place we must stack them on top of each other. Then it's tricky to select a particular vertex.

Use the "Segment End" option at Vertex sublevel. This way you can select a vertex by a click on a segment line, near the vertex.

Go to Left view. Create a NGon with eight sides. Center should be just in front of and slightly above the ear.

Convert to Editable Spline and delete the lower right segment. Select all vertices, right click and select "Corner" from the quad menu.
move the end point vertices so they follow the contour of the head.

 

 
It's time for a short pause in the spline modelling and take a look at the coordinate systems in 3D Studio. 
There are mainly two coordinate systems in use when modelling, "World" and "Local". In the top view, the world's positive X axis goes from left to right on the screen. The world's Y axis goes up the screen and the Z axis goes out of the screen towards the viewer. In this case, the spline was created in the left view, this will align the spline's local coordinate system to the left view. 
This is not the same as the world coordinate system. Switch to Perspective view (objects created in perspective view are always aligned to the world). Select the spline and click the move tool. Notice that the X, Y and Z axis are arraged as above description. This is true if the current coordinate system is set to "World". Change to "Local" system and see that the arrows are changing directions. Go to "Hierarchy" tab and click the "Affect Pivot Only" button. Then click "Align to world".
Don't foreget to uncheck the "Affect Pivot Only" button before you leave. One good thing about creating objects in an orthogonal views, is that the active grid, where the objects are created, are located at the world's origo. In this case it means that the head's vertical center line is placed at 0 at the world's X axis. This helps when we shall mirror (or use Symmetry) the other half of the head. Now back to the modelling.

Select the spline and go to "Spline" sublevel and select the spline. Seems like i'm repeating myself, but remember that a "Spline object" can have many "Spline subobjects".  Use the Outline tool to offset a new spline inside the original.
this is not really true, when Outline is used on open splines it will produce a closed spline. No new spline is created. Offsetting a closed spline will create a new spline.

Delete the short segment that connects the two splines.
Still in Spline sublevel, select the new slightly smaller spline and switch to front view.

Move the spline to the left. You should now have two "rails" running from the forehead and back to the backside of the neck.

   
In the left view, create a new eight sided Ngon right over the ear. Switch to front view and move the NGon to the base og the ear.

Select the main spline object and use the "Attach" tool to inwoke the new NGone into the main spline object.

 

Again use the Outline tool and create another spline from the newly attached Ngone at the ear.

Create yet another spline with the Outline tool. Move the vertices to adjust the shape like in the image to the right. The right most vertex should be at the corner of the eye.

 
Create one more eight sided shape with the Outline tool. Use the latest spline as original. This time change to front view and move the last created spline to the outer corner of the right eye.  
Now it's time to draw the cross sections. Set the Snap tool to "Vertex" only.

Click the "Create Line" button. Start at the topmost vertex and draw a spline all the way down to the neck. Make sure you snap to all the top and bottom vertices of all the eight sided splines.

Before adjusting the vertices, check "Area Selection" option.

 
Now that we have drawn the first cross section spline, there are two vertices in each spline crossings. Just selecting a vertex and move it will break the spline cage. Use Area Selection to prevent this. All vertices within the threshold value will be selected by a single click at a vertex. Another way is to use window selection instead.
Move the vertices along the right side of the head (left side on screen). Note that the last vertex in the cross section spline ended up in the middle of the neck. 

When there's no vertex to snap to then the vertex is creates at the working grid. Wich is 0 in the world's X axis when working in the left view. Drawing in the front view without snap will create object at 0 in the world's Y axis.

Before continuing with the next cross section, use the "Refine" tool to add a vertex in the ear.

Draw the next cross section. Start at the top of the forhead and end at the newly created vertex in the ear. 

The spline cage is beginning to take form. Now it's time to apply the Surface modifier.

Check the "Remove Interior Patches". At this stage the surface modifier can run into problems when it determines what's inside/outside of the model. Use "Flip Normals" to turn the surface inside out.
Also set the "Steps" to a lower value like 1, to reduce the polycount.

 

If you plan to animate the head then set the "Threshold" value to 0. This will propably make the surface disappear. Don't worry we will take  care of that soon. The threshold value tells the surface how close two vertices must be before they're considred "Fused" i.e. "At the same place". Do you remember the the talk about stacking vertices on top of each other erlier in this tutorial? We have now told the surface modifier that only vertices that are exactly at the same place should be a joint in the spline cage. Unfortunatley, the snap tools in 3D Studio is not that accurate. The vertices that was snapped together are to far away to be considered at the same place. Select two joint vertices and use the "Fuse" button to repair the inaccuracy of the snap tool. Once the vertices are fused together the surface will re-appear.
If the threshold value is too large then the spline cage will change if we animate the vertices so close that they will be treated as fused. By setting the threshold to 0 that risk is minimized.

Apply the "Symmetry" modifier (max 5 and above) to automaticly generate the other half of the head.

Set the mirror axis to Z and uncheck "Slice Along Mirror".

 

Forward to part 2