Envelope Sub-Object

Select an object with the Physique modifier. > Modify panel > Sub-Object Envelope

After Attach to Node is used to create links and envelopes in a hierarchy or if splines and bones are added using the Add command in the Physique Bones rollout, envelopes are adjusted using the tools in Envelope Sub-Object to correct the way skin behaves. Usually the first adjustment is to assign a rigid envelope to the characters head. The head should not deform with the deformation spline, a rigid envelope blends with other envelopes but retains the shape of the head.

Tools on the 3DS MAX toolbar can also be used. For example you can use the Non-Uniform Scale tool on envelopes and cross sections or use the Select and Move tool to move envelopes, cross sections, or control points on cross sections.

Envelopes are the basis of Physique's Blending. They provide smooth deformation of the skin across the joints. Envelopes are used to determine which links have influence over which vertices. Vertices falling between overlapping envelopes receive influence from each, thus creating a smoothly blended transition. Envelope sub-object level is where you can adjust envelopes to encompass more or fewer vertices or you can adjust the characteristics of an envelope such as its relative strength. The goal is to modify the envelopes so each vertex is encompassed by at least one link's envelope. The outer bounds should have sufficient overlap between links to provide a smooth blend at the joints.

Patches

Patch tangent handles do not need to be encompassed by an envelope to work. Only a patch vertex needs to be encompassed by an envelope. This relieves you having to scale the envelopes to a large size to encompass tangent handles.

Workflow

With Initial Skeletal Pose turned on, check that the envelopes cover all areas of the model. If you turn off Initial Skeletal Pose, the character adopts its animated position. Use an animation that stretches the character around such as a run or dance file, for example. Find a frame where the envelopes need adjusting and edit the envelope parameters. Changing the envelopes with the character in an animated position will always reference the Initial Skeletal Pose.

Indications that envelopes need adjustment include vertices that don't follow the skeleton. To correct for this increase the radial scale of an envelopes outer boundary. Vertices at joints get pushed or dented in. Too many envelopes may be affecting these vertices try reducing the inner bound radial scale and overlap values. Bending appears too linear or broken at the joint, the envelope's outer overlap values should be increased.

Procedure

To adjust envelopes around the biped's pelvis with Physique

Biped's Triangle Pelvis option on the Structure rollout was used here. The deformable envelope from the pelvis to the lower spine object is too small to correct the mesh problem in the pelvis area.

  1. Turn on Link and select the middle link.

  2. Select Both and increase the Radial Scale value until the outer envelope just surrounds the pelvis area.

    Both envelope bounds scale together.

  3. Increase the Parent Overlap value until the red envelope appears through the mesh.

    Decrease the Falloff value to strengthen this envelope if necessary. Adjust the thigh and buttock envelopes for overlap to finish correcting this area.

To select cross sections in the inner or outer bounds

Click the Inner or Outer button in the Envelope Parameters area if you want to work with cross sections solely in that part of the envelope. Click Both to be able to work with both Inner and Outer cross sections at the same time.

To copy an envelope and its settings to the mirrored link

  1. With the source link selected, click Copy to save the settings to the buffer.

  2. Select the mirror link and click Paste.

  3. Click Mirror and the selection immediately flips about the mirror axis.

  4. Use Rotate on the 3DS MAX toolbar to rotate the selection to the final orientation.

Interface

Link: Turn on to select links in the viewports and edit the selected links envelope parameters.

Turn on link, select a biceps link, CTRL+Click the opposite bicep to add it to the selection, then edit envelope parameters for both links at the same time for example.

Cross Section: Edit envelope cross sections to change envelope shape and area of influence.

Select a cross section on the inner or outer boundary of an envelope and then move or scale it. Non-Uniform Scale the cross section of the collar envelope to avoid vertices in the chest area, for example.

Control Point: Edit the control points on a cross section.

Select a point on a cross section of an envelope and reposition it to change an envelopes shape and area of influence.

Next/Previous: Move to the next or previous link, cross section or control point. This depends on Selection Level status.

Deformable: Enable or disable deformable envelopes for the selected link(s).

By default, deformable envelopes are red.

Rigid: Enable or disable rigid envelopes for the selected link(s).

By default, rigid envelopes are green.

Note: You can have deformable and rigid envelopes turned on for the same link. Normally, you use one or the other. By non-uniform scaling the rigid and deformable envelopes for one link, you could position one envelope on top of the other. For example, you could deform the shoulder with a rigid envelope and the armpit with a deformable envelope. Both envelopes can also be turned off for a link.

Partial Blending: Turns on partial blending for the selected link(s). Leave either a deformable or rigid envelope on and then turn on Partial Blending.

Physique calculates the weights of each link on a given vertex. If Partial Blending is off, and the total weight is less than 1, Physique normalizes the combined weight to 1. If Partial Blending is on, the weights are allowed to remain at a value of less than 1. The remainder is filled in by the root node, the equivalent of no influence. See How Partial Blending Calculates Weights for a detailed explanation of how the program calculates these values.

Partial Blending on all the deformable envelopes for the bones in this character's jaw allows smooth mesh deformation when the bones are moved.

Envelope Parameters

The Strength and Falloff values apply to both the Inner and Outer Envelopes bounds.

Strength: Changes the strength of the envelopes. Range=0 to 100; Default=1.

Used primarily for areas where envelopes overlap and you want one to be more influential than the other.

Falloff: Changes the rate of falloff between the Inner and Outer bounds of an envelope. This is a Bezier curve function. Range=0 to 1.0; Default=0.5.

Vertices within the inner bound are fully influenced (weight=1) and those beyond the outer bound get no influence from the link (weight=0). Falloff determines the rate at which the influence falls off from 1 to 0.

Inner: Turn on to change the values of the Inner bound.

Outer: Turn on to change the values of the Outer Bound.

Both: Turn on to change Values for both Inner and Outer Bounds at the same time. Changes to this value are equally applied to both the Inner and Outer Bounds.

Displayed values for Radial Scale and Overlap reflect the values for the Inner Bound when Both is selected.

Radial Scale: Scales envelope bounds radially. Range=0 to 100.

Parent Overlap: Changes the envelope overlap to the parent link in the hierarchy. Range= -1 to 10; Default=0.1.

A value of zero causes the end of the envelope to fall on the joint. Values less than 0 bring the envelope inside the link and values above 0 will overlap onto the adjoining link.

Child Overlap: Changes the envelopes overlap to the child link in the hierarchy. Range= -1 to 10; Default=0.1.

A value of zero causes the end of the envelope to fall on the joint. Values less than 0 bring the envelope inside the link and values above 0 will overlap onto the adjoining link.

Edit Commands

Command functions here will vary depending on whether Links, Cross Sections, or Control Points are turned on in the Selection Level area.

Insert: Inserts a cross section or control point on a cross section.

Delete: Deletes a Cross Section or Control Point.

Copy: Copies an Envelope or Cross Section.

Paste: Pastes an Envelope or Cross Section.

Mirror: Mirrors the envelopes on a selected link or mirrors selected cross sections in an envelope.

After a Mirror operation, click Rotate on the 3DS MAX toolbar, turn on Local coordinates, then click and drag over a Link or Cross Section to adjust orientation.

Note: To copy an envelope to its mirror, the sequence would be Copy, select the opposite link, Paste, then Mirror.

Exclude: Excludes links from influencing a selected link(s); a link will not blend with any link in its exclusion group. For example, exclude the right thigh link from influencing the left thigh link. Displays the modeless Exclusion dialog.

For example, rather than scaling the index finger envelopes to avoid vertex influence on the middle finger, exclude the middle finger links from the index finger links.

Exclude Envelopes dialog

Link Envelopes List (left side): Displays available links to exclude, selected links are not in this list.

Exclude Envelopes for Selected Links List (right side): Envelopes to exclude from the current link selection appear in the list. The text field displays the name of the selected link.

Right Arrow: Select links in the Link Envelopes List on the left, then click the right arrow to add them to the Exclude Envelopes for Selected Links list on the right.

Left Arrow: Select links in the Exclusion Envelopes for Selected Links list on the right of the dialog, then click the left arrow to remove them from the exclusion list.

Clear: Clear the Exclude Envelopes for Selected Links List. Selected links do not exclude other links.

Display Subtree: The Link Envelopes list increments links according to their level in the hierarchy. This visual aid can help you to find and select links.

Leave this modeless dialog open, choose a link or links in the viewports, select links to exclude in the Link Envelopes List on the left and use the Right Arrow to add them to the Exclusion list.

Note: To get the new exclude functionality in character studio 3 you must reinit old files with initial skeleton pose, and vertex assignments checked.

Interactive Redraw: Turn on to dynamically update the mesh when adjusting envelopes.

When this is off the mesh updates at the end of envelope size change.

Initial Skeletal Pose: Puts the mesh character in the pose it was in just before Physique was applied.

Shaded: Toggles shaded display of vertex weights in the viewports.

Display Options: Customize the envelope display. Displays the Blending Envelope Display Options dialog. As well as selecting what is displayed, the color for each parameter can be selected.

Selected Deformable/Rigid Envelope groups

All parameters except Control Points are on by default.

Inner: Toggle viewport display of inner envelopes. Change the viewport colors of the inner envelope boundary.

Outer: Toggle viewport display of outer envelopes. Change the viewport colors of an outer envelope boundary.

Weighted Vertices: Toggle viewport display of weighted vertices. Change viewport colors of weighted vertices.

Sides: Number of envelope sides in the viewport display.

Selected Envelope Cross Sections

Cross Sections: Toggle viewport display of cross sections. Change viewport colors of selected cross sections.

Control Points: Toggle viewport display of control points. Change viewport colors of selected control points.

Bezier Patch Handles: Set the viewport color of Bezier patch handles.

 

 

 


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