Modeling Work with meshes Ofsetting meshes to produce STL-ready objects > Offset a mesh

Create new geometry from meshes

How to generate new curves, surfaces, and meshes from existing meshes, to help in further modeling.

Project curves on meshes

How to project a curve, isoparm or surface edge onto one or several meshes.

Project a curve onto a mesh

Do one of the following:
Select one or more meshes, then choose Mesh > Mesh Curves > Mesh project curve from the tool palette.
Choose Mesh > Mesh Curves > Mesh project curve from the tool palette, then select one or more meshes, and press the Go button.
Select:
the curve(s) you want to project, in the view window that is perpendicular to the projection direction OR
a projection vector, then the curve(s) you want to project.
See Create or edit a reference vector



Press the Go button in the lower right hand corner.

Degree 1 NURBS curves are created on the mesh(es). They update if the input curve is modified.

These projected curves are often referred to as curves-on-mesh.

Project curves normal to meshes

How to project a curve perpendicular (normal) to one or several meshes.

The result of the projection is a degree 1 NURBS curve on the mesh. Construction history is supported so that if the input curve is modified, the degree 1 curve generated on the mesh updates.

Project a curve normal to a mesh

Do one of the following:
Select one or more meshes, then choose Mesh > Mesh Curves > Mesh project normal from the tool palette.
Choose Mesh > Mesh Curves > Mesh project normal from the tool palette, then select one or more meshes, and press the Go button.
Select one or more curves to project, then press the Go button.

The curves are projected onto the mesh(es) and degree 1 NURBS curves appear on the mesh.

Modify the input curves if necessary.

The projected curves on the mesh(es) update.

These projected curves are often referred to as curves-on-mesh.

Create curves at mesh intersections

How to creates curves at the intersections between two sets of meshes, or between a set of meshes and a set of surfaces.

You select two sets of meshes, or one set of meshes and one set of NURBS surfaces, and the tool creates curves at the intersections between them. You can later use the curves-on-mesh to cut the meshes, and the curves-on-surface to trim the surfaces.

See Cut meshes

See Trim a surface

Intersect two sets of meshes

Choose Mesh > Mesh Curves > Mesh intersect .
Select one or more meshes to intersect.



Press the Go button.
Select one or more meshes that intersect the first set of meshes.
Press the Go button when finished.



Degree 1 NURBS curves are created at the intersections between pairs of meshes (on both meshes).

These curves have history, so modifications to the meshes will cause them to update.

The intersection curves can then be used by the Mesh cut tool to cut the meshes.

Intersect a set of meshes with a set of surfaces

Choose Mesh > Mesh Curves > Mesh intersect
Select one or more meshes to intersect.
Press the Go button.
Select one or more surfaces to intersect with the meshes.



Alternatively, you can select the surfaces first and the meshes second.

Press the Go button when finished.



Degree 1 NURBS curves are created on the meshes where they intersect the surfaces. Curves-on-surfaces are created on the surfaces where they intersect the meshes.

All these curves have history, so modifications to the meshes or surfaces will cause them to update.

The curves on mesh can then be used by the Mesh cut tool to cut the meshes.The curves-on-surface can be used to trim the surfaces using the Trim surface tool.

Create degree 1 curves from mesh boundaries

How to create degree 1 NURBS curves from selected mesh boundaries.

Create degree 1 curves from mesh boundaries

Choose Mesh > Mesh Curves > Mesh Boundaries .
Select a mesh

All the mesh boundaries are highlighted in green.



Do one of the following:
Click on the boundary or boundaries you want to extract (they turn yellow), then press the Extract button at the bottom of the window.
Press the Extract All button at the bottom of the window to extract all boundaries.

One or more degree 1 NURBS curves are created and overlap the boundaries of the mesh.

Create theoretical intersection curve along feature

How to create theoretical intersection curves (and feature curves approximations) that can later be used for surface development.

An input curve (as an approximation of the feature curve) and radius of influence must be provided to calculate the theoretical intersection curve. If you do not have such a curve, you can input a series of points along the feature to create an approximation to the feature curve.

The output consists of a theoretical curve, and, if using the point method, a feature curve approximation. The feature curve attempts to lie on the mesh as much as possible. The theoretical curve is drawn where both sides of the mesh (across the feature curve) would intersect if they were extended. The theoretical curve generally lies off the mesh.

Preliminary steps

Turn on the Curvature Evaluation shader from the Diagnostic Shading panel.

This will show you areas of high curvature where you may want to define theoretical intersection (or feature) curves.



Optionally, create a curve along the mesh in the area where you want the feature line to lie. Using blend curves is recommended since you can constrain the blend points to the mesh.

To extract a theoretical curve from a mesh (curve method)

Choose Mesh > Mesh Curves > Mesh Extract Theoretical Intersection
Select the mesh

If the Show Curvature Evaluation option is on, the mesh is shaded with a curvature map.

Select an existing curve drawn along the feature

A blue radius manipulator appears at the start of the curve.



Adjust the radius through the option window or by dragging the mouse on the blue circle. (This value corresponds to the Tangent line distance in the option window).

Make sure the tube defined by the curve and radius is large enough to encompass the entire area of transition. That is, the outer edges of the tube should lie in the flatter mesh regions (green on curvature map).

If necessary, you can click along the curve to create extra radius manipulators and adjust them with the mouse (click and drag the small circle at the center to move a manipulator).

This creates a variable-radius cylinder and controls the shape of the resulting curve.

Press the Recalc button.

A degree 1 curve is produced: the theoretical intersection curve.

Tangent lines, drawn in yellow, show you where the tube intersects the mesh. They help you ensure that the radius is large enough to cover the entire transition region.



You can still add more radius manipulators or change others options in the option window then press Recalc to recompute.

To extract a theoretical curve and feature curve approximation from a mesh (point method)

Choose Mesh > Mesh Curves > Mesh Extract Theoretical Intersection
Select the mesh.

If the Show Curvature Evaluation option was on, the mesh is shaded with a curvature map.

Click down along the feature to position a series of points.

Each point appears with a blue radius manipulator and a cross in the middle. The cross can be selected to reposition the manipulator inside the feature.



Adjust the radii by dragging the mouse on the blue circles. Changing the Tangent line distance value in the option window will set all the radii to the same value.
Press the Recalc button.

An approximation feature curve is produced in addition to a theoretical intersection curve. Both curves have degree 1.

Tangent lines, drawn in yellow, show you where the tube intersects the mesh. They help you ensure that the radius is large enough to cover the entire transition region.



You can add more radius manipulators (by clicking on the feature curve) or change other options in the option window then press Recalc to recompute.

Reconstruct edges on meshes

How to create clean sharp edges over areas of high curvature in a mesh, or reconstruct the edge where two meshes meet, or the edge where a mesh meet one or more surfaces.

As with the Mesh Extract Theoretical Intersection tool, an input curve and radius of influence must be provided to define the direction of the sharp edge as well as the area where the surfaces will be built.

The curve can be a blend curve, theoretical curve, or curve-on-mesh, and doesn't have to lie completely on the geometry.

The edges on the mesh(es) are rebuilt as NURBS skin surfaces.

Edit > Undo can be used with this tool.

Preliminary steps

Turn on the Curvature Evaluation shader from the Diagnostic Shading panel.

This will show you areas of high curvature where you may want to create sharp edges.



Create a curve along the mesh as a first approximation to the sharp edge. To that effect, we suggest using:
The feature or theoretical curve output from the Mesh > Mesh Curves > Mesh Extract Theoretical Intersection tool.

or

A curve created with the BlendCrv Tools > Blend curve create tool, which lets you constrain the blend points to the mesh.

In the case of intersecting meshes, or meshes intersecting with surfaces, the resulting curves-on-mesh can be used.

To sharpen an area of a mesh

Choose Mesh > Mesh Edge Reconstruct
Select the mesh.
Press the Accept button.
Select the curve

A blue radius manipulator appears at the start of the curve.



Adjust the radius through the option window (Surface edge distance) or by dragging the mouse on the blue circle.

Make sure the tube defined by the curve and radius is large enough to encompass the area where you want to build the sharp edge. That is, the outer edges of the tube should lie in the flatter mesh regions (green on curvature map).

If necessary, you can click along the curve to create extra radius manipulators and adjust them with the mouse.

This creates a variable-radius cylinder and controls the shape of the surfaces.



Press the Create Surface At Edge button.

Two NURBS skin surfaces are produced, creating a sharp edge where they meet (at the theoretical intersection). The underlying mesh is removed.

Tangent lines show you where the tube intersects the mesh.



If the Create Fillet option was turned on, press the Fillet button to create a fillet between the two surfaces.

The surfaces are trimmed back to the edges of the fillet (where possible).

To reconstruct the edge between two meshes

Choose Mesh > Mesh Edge Reconstruct
Select the two meshes.

The meshes must have been previously intersected and cut so that only their edges touch.

Press the Accept button.

The two meshes are merged into one.

Select a curve along the common boundary between the two meshes.

A blue radius manipulator appears at the start of the curve.



Adjust the radius through the option window (Surface Edge Distance) or by dragging the mouse on the blue circle.
If necessary, you can click along the curve to create extra radius manipulators and adjust them with the mouse.

This creates a variable-radius cylinder and controls the shape of the surfaces.

Press the Create Surface At Edge button.

Two NURBS skin surfaces are produced, creating a sharp edge where they meet (at the theoretical intersection). The underlying mesh is removed.



If the Create Fillet option was turned on, press the Fillet button to create a fillet between the two surfaces.

The surfaces are trimmed back to the edges of the fillet (where possible).

To reconstruct the edge between a mesh and one or more surfaces

Choose Mesh > Mesh Edge Reconstruct
Select one mesh, and one or more surface(s).

The mesh must have been previously intersected with the surfaces and all geometry trimmed/cut to the intersection so that only their edges touch.

Press the Accept button.
Select a curve along the common boundary between the mesh and surface(s).

A blue radius manipulator appears at the start of the curve.



Adjust the radius through the option window (Surface Edge Distance) or by dragging the mouse on the blue circle.
If necessary, you can click along the curve to create extra radius manipulators and adjust them with the mouse.

This creates a variable-radius cylinder and controls the shape of the resulting surface.

Press the Create Surface At Edge button.

A single NURBS skin surface is produced on the mesh, creating a sharp edge where it meets the existing surface(s). The underlying mesh is removed.

If the Create Fillet option was turned on, press the Fillet button to create a fillet between the surfaces at the sharpened edge.

The surface is trimmed back to the edges of the fillet (where possible).

Create collar surfaces from meshes

How to create a collar NURBS surface along any boundary of a mesh, or curve-on-mesh.

The collar surface is fitted to the mesh along the selected curve (edge or otherwise) and provides continuity information along that curve, allowing you to build additional geometry from it.

A curve-on-mesh results from projecting a curve on a mesh, or intersecting meshes.

See Project curves on meshes

See Project curves normal to meshes

See Create curves at mesh intersections

Create a collar surface against a mesh

Choose Mesh > Mesh Collar .
Select a mesh

All the mesh boundaries, and curves-on-mesh, are highlighted in green.



Click at two locations along one of the green curves to specify a segment.

A collar surface is built along the curve, covering the shortest distance between the two points.



If the collar surface runs in the wrong direction, press the Reverse button.

On a curve-on-mesh, the Reverse button flips the collar to the other side of the curve, instead of changing its direction.

Click on more points, if necessary, to refine the shape of the collar. Each new point creates an extra segment (span).



Optionally, you can do the following:
Move the points (shown as green locators) along the curve. The collar surface updates interactively.
Change properties of the collar such as degree, width, number of spans per segment, and whether or not the collar is periodic (closed) through the option box. The collar surface updates interactively.
Press the Next button to create another collar surface without having to re-invoke the tool.

If you cannot achieve the desired shape with the default collar mode, delete the collar, re-enter the tool, set Fit Type to Ribbon, and repeat the procedure.

Only two points can be specified in Ribbon mode. Unlike in Surface mode, the collar is only fitted to the mesh at the boundary/curve that you selected, and not necessarily along its entire width.

You can then use NURBS modeling tools on the edge of the collar surfaces to build additional surfaces against the mesh.

Ofsetting meshes to produce STL-ready objects

How to offset meshes to produce STL-ready mesh objects.

This tool takes a mesh and produces a watertight STL mesh from it.

First it duplicates the original mesh, then creates a mesh offset, removes any problem vertices, and finally joins the mesh offset to the original mesh's duplicate to produce an STL-ready mesh.

Offset a mesh

Select a mesh

(or wait after entering the tool to select the mesh).



Double-click the Mesh > Mesh Offset icon to open the option box.
Choose the offset Distance (default is 1.0).
Press the Offset button.



A watertight mesh volume is created, ready for export to STL format.

The original mesh is kept.

Select another mesh to offset, if needed. You can only offset one mesh at a time.