Sub-Divisional Modeling

When working with sub-divisional modeling, a mesh surface in the form of a functional ‘skin’ is stretched over the polygonal surface of a solid.

By applying a mesh to the surface of a complex shape, specific contours of the model can be reshaped.

Primitives which are created as ‘solid’ objects should be converted to SMesh objects by selecting the part, then selecting the Smesh option from the Solid Mode of the Selection Info palette, or the 3D page of the Properties sheet.

A profile can be used as a Smesh after it has been converted to a surface using Format | Create Surface from Profile. This allows mesh modeling or facet extrusions to be done on a profile.

SMESH | smooth mesh

Example

In the example below, the facet of a Smesh object will be extruded along a path defined by a profile.

A profile is drawn as a 2D Rectangle in the workspace.

This is selected and converted to a surface using Format | Create Surface from Profile.

The Selection Info palette, shown below is used to convert the properties to Smesh.

Converting the properties of the Surface to a Smesh

A profile is drawn in the workspace, perpendicular to the workplane, shown below. This does not have to be associated to the SMesh object. This profile is drawn using the 2D Polyline tool.

The surface of the SMesh object can be extruded along the path defined by the profile shown below.

To do this, select Modify | Surface Mesh| Extrude Face then select the interior region to select the face to extrude, shown below.

At the prompt > select an entity for extrusion path, select the polyline profile. The result is shown below.

The transitional edges and surfaces of the SMesh are controlled by increasing the Smooth Property level in the Selection Info palette. In the example below, this level is increased to 3.

Modeling control can be exerted over the individual facets of the SMesh by exploding Select the object | Format | Explode the part, then using the Edit tool to select the specific facet to manipulate. In the example below, the selected facet is shown. In this example, the option to Ignore Backfacing is selected from the local menu.

By selecting one of the nodes of the selected facet, the surface can be manipulated in isolation to its associated edges and facets, shown below.

In the example below, the rendering is done with the foreground wireframe activated. To do this, right click on any render tool and select the Foreground Wireframe options.

Creating a Sub-Divisional Mesh on a Primitive Solid

In the example below, a Box is draw to measurements 50 x 80 x 100.

3D Primitive : Box = 50 x 80 x 100

The Box is then selected, and the 3D properties changed from Solid to SMesh, shown below.

Using the Selection Info Palette to adjust the Divisions

In the example below, the Box is selected and the number of width divisions is changed to 6. This distributes more polygonal segments across the width, allowing a greater degree of modeling functionality across this surface.

 

Converted to Smesh with additional width divisions added 

Smooth Mesh(SMesh)

Ribbon : Modify | Surface Mesh

Default Menu : Modify | Modify 3D Objetcts | Surface Mesh

Palette : Panels Setup | SMESH

The Smooth Mesh function is a form of sub-divisional solid modeling which allows fluid editing of faces, edges and transitional surfaces.By sub-dividing the model into various levels, more modeling control can be exerted over the meshed surfaces. By adjusting the smooth level of the division, curvatures can be added at each node point which can be independently or collectively modified.By sub dividing the model into specified levels along the length, width and height axes, each division can be controlled through the use of nodes, allowing faces to be merged or extruded.

Smooth Level

The smooth level of the SMesh determines the amount of tesselation The polygonal mesh surface on the transitional surfaces between the edges and facets. In the example below, the Smooth Level is increased to Level 4.

Increasing the smooth level between edges and facets

 

Selecting the Nodes

By exploding the part and using the Edit tool, the individual nodes of the polygonal segments shown below can be selected for modeling.

Exploding the part, then selecting using the Edit tool.

Sub divisional nodes

When a model is sub-divided into levels, nodes are applied to each corner of the facet, or connecting point of the curve. These nodes can be selected individually or in multiples so that surfaces can be more fluidly remodeled.

3D Primitive : Sphere

Converted to SMesh, nodes selected

Selected Nodes manipulated 

Smooth level increased to 4

Rendered with surface mesh visible 

Extruding/Merging selected faces

Ribbon : Modify | Surface Mesh

Default Menu : Modify | Modify 3D Objetcts | Surface Mesh

Palette : Panels Setup | SMESH

Selected faces of the mesh can be extruded by exerting modeling control over only the selected facets.

In the example below, a Box is converted from a Solid to a SMesh.

Additional Width divisions are added by selecting the part and adjusting the width divisions in the Selection Info palette.

The part is exploded using Format | Explode, then the Edit Right click in the workspace, select Edit tool. tool is used to select the Part. This allows the vertice of each node to be selected, shown below.

To select independent facets, deactivate the Selector mode at the base of the workspace, shown below.

Hold down the SHIFT key and select similar faces to those shown below. The view can be turned to the Right side for this task if preferred. In the example below, the view is rotated by long-pressing the mouse wheel and rotating the view visually.

Selecting individual facets

To extrude the selected facets, right click and select Extrude Faces from the local menu of select this option from the Status bar at the bottom left of the workspace.

Select any of the nodes within the selection and drag them in a parallel plane. In the example below, the extrusion is external to the original face.

The result is shown below.

Take Note 

Selected facets can be merged and deleted using a similar method, shown below.

Merging Facets

Adjacent, neighboring faces (where the sides of the face are aligned) can be merged to create a single surface. In this example, several adjacent faces will be merged to create a single profile, then extruded outwards.

Make sure the model is restored to its original format, using the Undo option. The model should still be identified as SMesh in the Selection Info Palette.

Use the Edit Node tool to select the model, then zoom into the faces shown below and use the same technique to select the indicated faces.

Right click and select the Merge Facet option to create a single merged profile of the selected faces. The result should be similar to the illustration below.

The illustration right has been graphically enhanced to show the newly created face.

To extrude this face, reselect inside the new shape, shown above, then select the Extrude option.

Extrude the face outwards, shown below.

The result is shown below.

Surface on Face | Offset

A local menu option Offset has been added to the Surface on Face tool. This defines the offset of the surface from the object. When the surface is being created, user has this option to create it with a positive or negative offset from the source object.

Positive Offset

Negative Offset