modo is a polygon modeling tool For all intents and purposes modeling wise, modo is a polygon modeling tool. Yes, other options are provided for generating forms, such as spline and bezier curve patching, or working with different types of subdivision surfaces, but the ultimate goal of those operations is to eventually create polygons for rendering or for export to their ultimate destination. modo provides a variety of ways to manipulate and shape those polygons into the desired shape. Some tools manipulate polygons directly, such as the transform and deform tools, others provide means to manipulate polygons indirectly, such as the sculpting of subdivision surface models with a displacement map. There are as many methodologies to reaching a finished result as there are users, everyone has their own unique approach, but of the various styles, there are some basics to understand for modo's way of working that will ease the overall learning curve allowing each user to reach their goal and find their own individual style.
Components versus Items One of the areas that is often confusing to new users of modo are the various selection modes. When modeling, users work in the three component modes -'Vertices', 'Edges' and 'Polygons', this is where the actual geometry is created and shaped. 'Items' mode is useful for positioning modeled object in a scene for final render and is a necessity of Animation. When in any individual selection mode, only selections of that type can be made. The important distinction is that when editing an Item, users are editing the layer itself (think of it like a container), while editing a component is editing the contents of the layer (what's inside the container). Modifications made in the Vertex, Edge and Polygon modes happen around the center point, while transforms applied while in Item mode move the entire item including its center point.
Interacting with modo Interacting with modo itself is done mostly through the manipulation of the mouse, taking advantage of all three buttons and the scroll wheel (some may prefer a trackball or tablet, both typically have functions that can be remapped to mimic the options available on a mouse). Mouse button activity is supplemented by keyboard commands, which are at times used in unison with the mouse. This can take some getting used to. (see Mousing Standards for more information) Given that modo is a 3D application that users interact with in a 2D fashion, this may at times feel awkward, but produces the most predictable results given today's technology (Hey, where's my 3D monitor and force feedback gloves?).
Users are encouraged to read through the interface section of the documentation; familiarizing oneself with the many viewports, tabs and panels will help in working in modo. Nothing kills the creative impulse more quickly than fruitlessly searching for some often used tool or function. The organization of modo is designed to reduce this as much as possible. Main functions are organized as Tabs across the top, such as Modeling, Sculpting or Rendering. When in any of these areas, only the tools necessary for the task at hand are provided, streamlining the process. This way of working also makes it easy to jump in and out of tasks easily, providing for a comfortable non-linear workflow. Users can model, render, animate and then model some more with very little worry that one process will have a negative affect on the others. In fact, a non-linear workflow is encouraged in modo. Users should be rendering and tweaking along the way toward the final result. This is meant to eliminate a lot of the guess work and surprises traditionally associated with creating in '3D'.
Using Tools To perform an operation, users must left mouse button (LMB) click on the tool icon or menu option. For one shot commands, such as 'Delete', 'Fit' or 'Hide', that is all that is necessary to produce a result. For interactive tools, like 'Move', 'Rotate' and 'Bevel', this makes the tool active and draws the appropriate tool handle within the 3D viewport, displaying the necessary Property options. To produce a result users will need to either 'Haul' somewhere in the viewport (hauling is the act of LMB+click dragging the mouse pointer left/right or up/down within the viewport with an active tool and can only be done while a tools is active) or hover the mouse pointer over the tools handles and then LMB+click and drag when a single handle turns a yellow color, constraining the action to a specific axis. Additionally, users can interact by changing values in the properties form, by default under the toolbox. Modifying values won't affect what's displayed in the viewport unless the user LMB+clicks somewhere in the 3D view to activate interactive mode for the tool, then modification to attribute values will update in real time in the viewport providing interactive feedback. When the desired result for a tool is achieved, users can simply drop the tool by pressing the 'Esc' or 'Q' keys to finalize the application of it. Once a tool is dropped, interactive editing of tool attributes is no longer possible.
Work Plane Users should understand that actions don't arbitrarily happen in 3D space within a viewport. For example, when creating points, the individual vertices are created at the intersection of the 'Work Plane' and where the user clicks in the viewport, providing predictable and repeatable results. Understanding the workplane and its functions is important to understanding how modo works. The Work Plane is the light gray grid that is visible in any viewport. In a perspective view, users may notice that the grid will change position; this is the Work Plane orienting itself toward the user, trying to stay as close as possible to parallel with the viewport window, while remaining aligned to the nearest axis. Users can also modify the Work Plane to a fixed arbitrary position, based on a component selection. This temporarily orients the entire modo universe to align with that selection, so all functions now work in relation to the Work Plane making it easier to perform task that would be very difficult otherwise. For more information regarding using the Work Plane, please reference that page of the documentation.
Action Centers When performing any action on a selection, the position of the center of origin and the axis orientation of the tool handle itself has a dramatic effect over the result when applied. Yes, users can orient the Work Plane to suit many situations, but constantly modifying the Work Plane would get tedious, so modo has what are called 'Action Centers', automatic combinations of center positions and axis directions for tools. There are a variety of options, based on different criteria; some are oriented to selections, some to a viewports orientation, while others are based on fixed positions, like the items center (0,0,0). Action Centers often packaged with tools to provide specific functions. Take for instance the Flex tool, this combines a rotation tool, with an action center that orients itself automatically to the selection border making it easy to pose characters. Understanding Action centers are necessary to a fluid experience with modo, it is recommended users reference the Action Center page for more information on working with them.
Falloffs Ordinarily, when performing an action on a selection, the application is uniform across the selection area. Falloffs provide a means to vary the strength of the action across a given area. Once activated, all of modo's tools respect the falloffs and apply themselves appropriately, opening up a variety of option that would be incredibly difficulty to reproduce otherwise. When enabled, a Falloff will snap to a selection when a tool is active, scaling to fit within the selections bounding box making them incredibly easy to apply and use. Falloffs can also be packaged along with tools, and often are. They are the basis of the many deformation tools - Rotate combined with a linear falloff produces the Twist tool, Move combined with the same falloff produces the Shear effect. Falloffs may appear simple, but wield an incredible amount of power when working in modo. For more information on using and applying Falloffs, please reference that section of the documentation.
History and modo When users apply a function that produces undesirable results (or they simply chang their mind), previous commands can be un-done by way of the command history list, a listing of all the functions applied in a scene. Pressing the Ctrl/⌘+Z steps users back through the command history , up to the maximum number of steps defined by the preference setting (100 by default). The modo Command History is held in a buffer while modo is open, but is not saved with the specific scene. Once a scene is closed, the Command History is cleared, freeing the memory for the next operation. For more on using the Command History, please reference that page of the documentation.