The LionSnake Modeler
User's guide
You downloaded the LionSnake Modeler from off of the Internet, so I thought it a fair bet that you also had a Web browser.
The Basics
You can use the LSM to create, edit, save, and load posable triangle meshes. I designed it for use with the excellent Persistence of Vision Ray Tracer, which you can download for free at www.povray.org.
First,
You need to have an active project open. You can open an existing file or create a new project; these options are found under the File menu.
The Objects
There are five objects you can manipulate:
- Knobs: These are diamond-shaped objects that form the joints of the skeleton.
- Parts: These are cyan lines that run between the joints of the skeleton. You can edit them by moving their end points, or double-click on them to edit their properties.
- Vertices: These mark the corners of the polygon mesh. They appear as small white squares.
- Edges: These are lines of varying color that represent the edges of the triangles. The color varies depending on the number of triangles that border on the edge: Edges with no faces are brown, edges with one face are pink, and edges with two faces are gray.
- Faces: Currently only triangular faces are supported. These aren't really shown; you have to deduce their presence by observing the color of their bordering edges. Texturing is not yet supported.
The Mouse Controls
As the mouse is moved around the screen, the items it rolls over will be highlighted if you can directly modify them in some way. Clicking the buttons has varied effects:
- Left button, no keys: Click and drag vertices or knobs to move them. Double-click vertices and parts to edit their values. Clicking on a vertex will mark it for dragging, extruding, detachment from parts, or attachment to parts. Clicking off of any item somewhere else and drag to mark a rectangle full of items.
- Control + left button: Press and hold either control key, then click and drag with the left mouse button, to move marked items with the mouse.
- Right button: The right button, with no keys held down, summons the pop-up menu.
- Control + right button: Press and hold either control key, then click and drag with the right mouse button. The view window will be dragged around with the mouse.
- Shift + right button: Press and hold either shift key, then click and drag with the right mouse button. The view will be zoomed in (for downward movement) or out (for upward movement).
- Control + shift + right button: Press and hold both shift and control, and then click and drag with the right mouse button, to rotate the view around the center of the screen. This is very useful for getting a good look at your model from all angles. The view rotates around an axis passing through the viewpoint(the center of the screen). The axis is perpendicular to the line going from where the mouse button was first clicked to its present location.
Adding objects:
- Parts: Select Add->Parts from either the pull-down or the popup menu. Select where you want a part to begin, click with the left mouse button to start, and drag the mouse to where you want the end point to be. Click to complete the part and start another. Click with the right button to stop (the part in work will be deleted).
- Vertices: Select Add->Vertices from either the pull-down menu or the popup menu. Click with the left mouse button to place vertices. Click with the right moust button to stop.
- Edges: Select Add->Edges from either the pull-down menu or the popup menu. Click with the left mouse button to start an edge, click somewhere else to finish that edge and start another. Click with the right moust button to stop; the edge in work will be deleted. If you put the mouse over an existing vertex during edge creation, so that the vertex is highlighted, that vertex will be used if you click.
- Faces: Select Add->Faces from either the pull-down menu or the popup menu. Click with the left mouse button to start a face, click somewhere else to establish the second corner, and click in a third place to finish the triangle and start another. The second triangle will use the same starting point as the first one, so that all of the triangles you make will make a fan. Click with the right mouse button to stop; the triangle being created will be removed. As with edge creation, triangle creation will make use of existing vertices and edges if you click while the vertex is highlighted.
Moving individual vertices
You can drag individual vertices by clicking and dragging them.
Marking individual vertices
Clicking on a vertex will mark it and clear the rest.
Marking groups of vertices
Click away from any vertices and edges to start a selection box. Drag it to contain what you want marked, and release the left button to make the selection. Everything inside the box will be selected, and everything out of the box will be cleared.
Extrude edges
Mark one or more edges (by selecting its end vertices) and then select Extrude from the context menu. The edges will be copied, with a pair of triangles created to adjoin the originals to the copies. Left-click with the control key pressed to drag the new edges.
Attaching the mesh to the skeleton
This is most important for using the posing function. Mark one or more vertices and choose Attach vertices from the menu. Move the mouse to the part to which you want to attach the vertices. When the part you choose is highlighted, click with the left mouse button. The marked vertices will be unmarked. Now when you move that part, the vertices (and any edges or triangles built on those vertices) will move with them. Vertices move depending on which end of the part was closer when they were attached.
Detaching the mesh from the skeleton
Mark one or more vertices, and choose Detach vertices from the menu. The marked vertices will no longer track the part they were attached to.
You do not have to detach vertices from one part in order to attach them to another.
Transforms
There are several transform options available either as a key command (the first letter of the transform name) or from the pop-up menu. When you select these transforms (as opposed to using the mouse to transform by hand), a dialog box will appear to get more info.
- Scale: A dialog box will appear that enables you to scale x, y, and z by different values.
- Uniform scale: A dialog box will solicit a single value. This will be applied to all three components of each vertex
- Rotate: The affected vertices will be rotated around the x axis, then the y axis, then the z axis.
- Translate: The affected points will be moved by the specified amount.
- Matrix: The matrix you supply is applied to the affected points. Very useful for shearing.
Files
- You can load and save files to the LSM's own format, which preserves all of the information that the LSM manipulates.
- You can also export POV-readable mesh files (they will have .msh as their extension). This exports only the triangles.
Keyboard commands
The following keys execute the following functions:
Ctrl+A | Toggles display of the axes |
X | Extrude |
M | Matrix transform |
R | Rotate transform |
S | Scale transform |
T | Translate transform |
+ | Zoom in |
- | Zoom out |
Delete | Delete marked vertices |
Home | Move the view to the origin |
Space | Toggle marking of the highlighted vertex |
Ctrl+Tab | Activate next project |
Ctrl+Shift+Tab | Activate previous project |
My To-Do List
As you can doubtless see, this modeler is barely functional. I already plan to add the following functions:
- PCM file import and export;
- Subdivision surfaces;
- Texturing;
- Dynamically-posable models (posable by variables in the script that calls the file);
- Inverse kinematics;
- Keyframing (or some other kind of animaton support);
- Physical properties simulation.
Furthermore, I might make my own custom compile of POV-Ray to include quadrilateral faces in polygon meshes; if so, I'll add support for them to this modeler.