Wednesday, January 13, 2010

Summary of Commands

Here is a summary of the commands we saw over the last classes:

Select the perspective camera on the outliner, click twice on their icon and on the attribute editor modify the near clip plane and far clip plane values to 0.1 and 10,000 respectively; then do it for the other cameras.
If you do not find an object on the screen or cannot zoom properly on it, go to the outliner and select the object by its name and then for whatever panel you are on –suppose it is the perspective view- you will find a series of local menus, and the first one is View. Then you can find the selected object by View/Frame Selection or View/Look at Selection or View/Frame All.

Center Pivot:
If you want to rotate, scale, etc and object sometimes you will notice that the pivot/handle is not on the center of the object and you will need to go to
Modify/Center Pivot to correct that position and rotate, move or scale properly.

Cv curve tool:
Create/CV Curve Tool
Degree 1 curve makes straight lines
Degree 3 curve makes splines

Surfaces from curves:
The surfaces are obtained by selecting 2 consecutive curves and lofting, on ‘objects hierarchy’ (green icon on top shelf). For multiple curve surfaces, it is recommended to loft the first 2 curves, then select and loft the last curve with the following one, and so on…instead of selecting all curves at once –the latter may cause unprecise folds or surfaces out of control-.
The control is obtained by modifying relative position of cv’s after selecting curve and going to ‘components hierarchy’ (blue icon on top shelf).
Produce curves that have sober inflexions, and no more than 12 or 15 cv’s.
Working in this manner, you will obtain bodies made out of continuous folds that have smoothness in the direction of the predominant vector of the curvature.
Curves need to be obtained out of the first originating curve, by duplicating it and displacing it or editing the cv’s of them, therefore ensuring that there will be geometric cohesion/correspondence between all curves to be lofted.
At any point in time you can rebuild the curves to add or subtract spans for further editing; this causes change on the curve.
Curves should be understood as made out of straight segments with specific bending moments; for this when using the spline curve create intervals between sets of 3cv’s and those intervals can approach straightness depending on how you displace/accommodate the first and last cv of each group of 3, so you will have the first cv, then an interval and the first set of 3 cv’s producing a bend, then another interval followed by the next bend with 3 cv’s and so on, and lastly one cv to stop the spline. You can edit the form of the overall spline by selecting a set of 3 cv’s and scaling up or down for more relaxed or tighter effect at that particular bend, and the more the first and last of these 3 cv’s stand on the trajectory of the curve, the more you can control the straightness or slight arch of the intervals.
You can also add more cv’s to a curve, for more detail at a specific spot, but then the following curve that is used to loft with this one will need that extra cv as well.
Surfaces will have a dependency to the ‘history’ of the curves so you will notice that when you select a curve that affects such surface it will turn magenta.
If needed you can kill the history/dependency of that object by going to Edit/Delete by Type/delete History


Edit Curves/ Rebuild Curves
Edit Nurbs/Rebuild Surfaces

Add point:
Edit Curves/Insert Knot
Select the curve in ‘object bhierarchy’ then right click in space and select Curve Point and drag alongb the curve to a desired position, then go to Insert Knot. It will not fall exactly on nthat space but rather it will split the difference between that new position and the most immediate cv and you can then manually move it and have extra geometry to manipulate the curve.

You can explore all other editing commands for curves and surfaces under Edit Curves and Edit Nurbs menus (such as Attaching, Dettaching, Trim, Fillet, etc.)

Extracting a curve from an existing surface:
Select a surface, right click in space and select ‘isoparm’, then select any edge or internal existent isoparm and drag to desired position; then go to Edit Nurbs/Duplicate Surface Curves and you will obtain a new curve on that position.
Isoparms are not curves they are only a geometric virtual description of a surface, but you can select any number of isoparms holding shift, and turn them into curves for new purposes.

Surface Display:
A surface will show more smoothness or refinement by selecting it and then typing 1, 2, or 3. If you want to visualize it shaded type 5, and 4 for going back to wireframe display.

Channel Box, Layers, Attribute Editor:
The extreme right of the top shelf has 3 icons; the first one is the attribute editor that shows characteristics of any selected object (number of cv’s/spans, etc) and the third one will open up a column with the channel box and the layer editor.
The channel box will display translate, scale, and rotate precise numbers for all manipulations to objects in ‘object hierarchy’ and you can edit those conditions by typing precise numbers in those boxes.
The layer editor allows to create layers, and then click twice on the new one so you can name it and assign it a color; then select the desired objects, right click over the target layer and click ‘Add Selected Objects’.

Materials, Shaders:
Window/Rendering Editors/Hypershade
On the Hypershade you can create materials under ‘create’ and it is recommended to use blinn and phong for shiny surfaces and lambert for opaque ones; once you create the material select the desired object then right click on the material and click on Assign Initial Shading Group to Selection.
You can change the color, transparency, incandescence of the shaders by clicking twice on the material and clicking on the shaded little icon for the color –will open up a spectrum of colors and intensities-.

When you need to move, scale, rotate, duplicate a number of surfaces and their origin curves, group them and then open/expand the group from the outliner clicking on the + sign, and within that set of curves and surfaces, group just the curves and only move, rotate or scale the grouped curves and this will affect the surfaces and the larger
group as well.
If you want to duplicate the whole group make sure to select duplicate
input graph on the duplicate options, so it extends the history dependences to the new group as well.

Deformers- nonlinear
For this you need to set up the Animation Mode on the top extreme left tab (otherwise you should always be on Modeling or Surfaces Mode)
Deform/Create Nonlinear/Bend, Flare, Sine, etc
Select an object or group of objects –if it’s a group always sel ct it directly by its name on the outliner- and apply a deformer. Initially this will not seem to have any effect, so while the deformer is actively selected go to the channel box and find midway the name of the deformer under ‘input’; click on the name of the deformer and it will open up different parameters; change those numbers and you will see the deformation that registers on the object. You can also rotate, scale the deformer and affect the piece in that way; it gives you indirect global control over an object or group of objects, without having to go to every single cv of the curves that made them.
Once finished with a particular deformer you need to kill the dependency to it, otherwise the whle group will keep reacting to it in unexpected ways.

Deform/Create Lattice
This is one of the most effective deformers, it can control both globally and locally with enough detail, depending on the density of the lattice you create (you can set that from the settings of the menu, which you will open clicking on the little square icon attached to the command before applying the lattice). It displays cv’s in component hierarchy so that they have weight of influence over the sector relative to the position of those selected cv’s.

Select first the target object, then the base object - Deform/Create Blendshape
Make sure that the settings of the blendshape are World and Target Options: in-between.
It establishes a relationship of morphing between a base object and a modified version of it separated by a certain distance, for the purpose of obtaining a transformation and subsequent intermediate steps (using animated snapshot)
After creating the blendshape you want to access the Blendshape editor to be able to see the transformation live. Window/Animation Editors/Blendshape; that will open up a dialogue box, in there you can move the handle up and down and see the base morphing into the target shape.
The next step is to set up an animation and play it. Set up the timeliner (bottom of the screen) so that the origin is 0 and the end is 120; change the numbers on the 2 left boxes at the start of the timeliner to be 0 and the 2 right boxes on the end of the timeliner to be 120. that sets up the duration of the animation. You also need to set up the speed, and this you can do at Window/SettingsPreferences/Preferences/Timeline by selecting the PlayBack Speed to be real Time (24 frames per second).
Then manually move the timeliner handle to 0, then select th base object and go to the blendshape editor dialogue box and move the handle all the way down to; then in there press ‘key’ and then go to Animate/Set Key (or just press ‘s’ on your keyboard). So far you have just set the start of the animation; now click away to deselect the base object and manually move the handle of the timeliner all the way to 120; then select again the base object, go to the Blendshape editor and move the handle all the way up to 1; then click on ‘key’; finally, repeat Animate/Set Key (or just press ‘s’ on your keyboard).
Now on the timeliner you can play the animation using the play, stop, etc commands or by manually moving the handle.

Animation Snapshot:
Animate/Create Animation Snapshot
Select the base and before creating the animated snapshot set the settings like this:
Timerange: Timeslider
Increment: if you have an animation of 120 frames, then typing 12 will produce 10 objects between the base and the target.
Update: Fast
You will obtain a series of step-by-step for the mutation of the base into the target. You can use it to select intermediate states for further manipulation or you can also set the increments so that then you can loft in between edges of the steps and obtain a pattern of transformation, a continuous surface informed by a motion of mutation of states (select isoparms at edges of surfaces of 2 consecutive snapshot steps and directly loft these 2 isoparms; for the purpose of lofting they are as good as curves, or just turn them into curves and then loft)

To edit the Animation Snapshot:
After the animated snapshot has been created, you will find on the outliner a group called Snapshot1Group, which contains the steps or snapshot objects.
You can edit the base or the target object and change its form or relative position/rotation and obtain an update for the steps in-between by selecting the Snapshot1Group form the list on the outliner and then
Animate/Update Motion Trail-Snapshot
This will update the animated snapshot without having to produce any new animation.

Exporting/Importing to and from Rhino:
Make sure that the units for maya ar congruent with the units you use on rhino and autocad: Window/SettingsPreferences/Preferences/Settings/Working Units
When you import an IGES created in rhino to maya (File/Import) group them and then select that group name from the outliner and scale it up 10 or down 0.1 in x,y and z and that brings it to position (there is a scale increment of 10 between maya and rhino).
When exporting from maya (File/Export Selection) you may not find the IGES option.
Then you must go to Window/SettingsPreferences/Plug-in Manager and set on all plugins.

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