Licom Systems Ltd.,

Training Course Notes

3D Surface Creation

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Licom Systems Ltd.Table of Contents

Work Volume and Work Planes . . . . . . . . . . . . . . . . . . . . . . . . . . .1Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Work Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1Work Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Work Plane Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2Slice through Work Volume . . . . . . . . . . . . . . . . . . . . . . . . . .22 lines for X and Y-axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2Existing Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2Parallel to the current plane . . . . . . . . . . . . . . . . . . . . . . . . . .2Reverse Current Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2As Current Plane, Different Origin . . . . . . . . . . . . . . . . . . . . .2By Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Set Work Plane Origin . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Work Plane Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Cancel Work Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Best Fit Plane through Points . . . . . . . . . . . . . . . . . . . . . . . . .3Make local axis Horizontal . . . . . . . . . . . . . . . . . . . . . . . . . . .33D Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33D Part Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

What is a Surface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Surface Creation Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4Flat Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5Extruded Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Ruled Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Ruled Surface Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7Swept Surface (2 Curves) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Swept Surface (2 Curves) Example . . . . . . . . . . . . . . . . . . . . . .8Swept Surface (3 Curves) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Swept Surface (3 Curves) Example . . . . . . . . . . . . . . . . . . . . . .9Revolved Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Revolved Surface Example . . . . . . . . . . . . . . . . . . . . . . . . . .10Rotation Direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Coons Patch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11Coons Patch 3 and 4 Curves Example . . . . . . . . . . . . . . . . . .11Fillet 2 Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Surface from Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Surface From Sections Example. . . . . . . . . . . . . . . . . . . . . . . . .13

3D Surface Editing Commands . . . . . . . . . . . . . . . . . . . . . . . . . . .14Break Intersecting Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Edit Surface Control Points . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Un-Trim Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Extend Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Surface Finder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Extract Edges from Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Convert to STL Facets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

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Licom Systems Ltd.3D Surface Creation

Work Volume and Work PlanesOverviewThe work volume and work planes are controlled from the 3D menu. The 3D and WorkPlanes Button Bars contain shortcuts to the work volume and work plane commands.

The Work Plane tab on the Project Manager allows easier manipulation and naming of thework planes.

Work VolumeA work volume is a rectangular volume, which encloses the machining envelope of thepart, or features that are to be machined. The work volume defines the position of X,Y,ZZero and the display limits of the work planes.

Work PlaneA work plane is a 2 dimensional section through the work volume on which 2D geometryis drawn and machined. The orientation of the plane is used by the post processor tooutput the correct indexing data. Work planes may be defined in several ways dependentupon the information available.

3D work volumes and work planes are utilised for 3D applications for surface edgecreation.

NOTE: - The format of the NC code is controlled by the post processor configuration. Itdetermines whether the co-ordinates are Local or Global and what indexing is allowed. Insome cases several posts are used for the same machine to create the NC code for specificrequirements

When creating work planes to control machining you MUST ensure that:

1 The Z axis points out of the plane.This is the side from which the cutting tool will approach the job.

2 The X and Y axis are in the correct orientation.Remember in the way your machine orientates the plane perpendicular to the tool.

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Licom Systems Ltd.3D Surface CreationWork Plane Commands.

Slice through Work Volume .

This is achieved by selecting a line, The view in which the line is picked is used to controlthe direction of cut. Lines selected in the ISO view will always produce a vertical slice.

2 lines for X and Y-axes

Any two lines that represent the X and Y-axis can be selected. The first line selected willdefine the X-axis. The second line selected, which must lie in the required X, Y plane, willdefine the orientation of the X, Y and Z-axes. The lines selected MUST be connected atone end.

Existing Geometry

This command is used to activate the work plane to which the selected geometry isassociated. When geometry is created it is linked to the current work plane.

Parallel to the current plane

This allows a new work plane to be activated which is parallel to the current plane byspecifying an offset in the local Z-axis.

Reverse Current Plane

This allows the four axis orientations to be cycled through

As Current Plane, Different Origin

This will create a duplicate of the active work plane upon which a different local origincan be set.

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Licom Systems Ltd.3D Surface Creation

By Name

Allows work planes to be selected or their properties to be edited from a list of all currentwork planes. Empty redundant Work Planes used can be deleted from the list.

Set Work Plane Origin

This allows the local origin on the current plane to be repositioned.

Work Plane Properties

Work plane properties allow work planes to be named and work plane offset number tobe specified.

Cancel Work Plane

This deactivates the current work plane and returns the status to Flat Land (normal 2D)

Best Fit Plane through PointsThis will create a work plane that fits best between various points. The points will beextracted from the items selected (Geometries, Polylines, Splines, and Surfaces).

Make local axis HorizontalThis will alter the current plane or cycle through all work planes, and re-orientate eachwork plane so that the specified axis, X or Y, is horizontal.

This is usually used when models have been imported.

3D Project

This allows geometry/toolpaths to be projected from one plane to another.

3D Part RotationThis displays a dialog that allows the job to rotated about an axis or so that a planedefined by 3 points is horizontal.

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Licom Systems Ltd.3D Surface Creation

What is a Surface.A surface is an mathematical description of the outer skin of a part. Therefore surfaceshave no thickness and cannot be seen when looking perpendicular to the edge.

The diagram opposite shows a flat surface. It can be seen in the YZ view (bottom left) thatthe surface is displayed as a line though mathematically its value is ZERO.

If the shaded view is rotated to look on the edge it would disappear.

Surface Creation Methods3D surfaces can be created in a number of ways defending upon the number and form ofthe geometrical edge definition.

Within AlphaCAM there are currently 11 methods for creating 3D surfaces.

When creating a surface you have to specify an Edge Tolerance. The smaller the edgetolerance the finer the the surface detail, this however increases the storage size of thesurface. The edge tolerance should be set with regard to the size and detail in the surface.

E.G.

Setting the edged tolerance for the Surface of a car roof to .1 would be ok but it would beto course for an electrode 20mm Diameter this would be set around .005.

The edge tolerance will be used in determining the number of steps along the first edge. Ifthe number of steps along first edge is altered this will affect the density of the surfacedetail. The greater the number of steps the finer and more complex the surface.

Surfaces edges cannot contain sharp corners. as any geometries or polylines are convertedto splines for the surface edge.

If a surface needs a sharp corner it has to be made from two surfaces.

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Licom Systems Ltd.3D Surface CreationFlat SurfaceThe Flat Surface Command will create a flat surface which is bounded by a close profile.The boundary profile must lie in one plane and be Geometry or Polylines not a Spline.

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Licom Systems Ltd.3D Surface CreationExtruded SurfaceThe Extrude Surface Command will create a of flat surface for each element in the profileselected. Each surface is extruded with respect to the Z axis of the plane of thegeometry.The profile must be Geometry or Polylines but not a Spline.

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Licom Systems Ltd.3D Surface CreationRuled SurfaceThe Ruled Surface Command will create one surface, (different to the extruded surface),which is suspended between two edge curves. The edge curves can, be open or closed, liein different planes, and be either, geometry, polylines, splines or surface edge. The startpoint of each edge curve will be connected with a straight line, this straight edges ismoved along each edge curve to generate the surface, hence its type name. When creatinga ruled surface with open edges, If the edges are in different directions, i.e.drawn opposite,a warning dialog will be displayed, with an option to automatically reverse one of theedges. When creating a ruled surface with closed edges it is important to ensure the startpoints are perpendicular otherwise the surface will be twisted.

Ruled Surface ExampleUsing the training example produce the surface opposite.

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Licom Systems Ltd.3D Surface CreationSwept Surface (2 Curves)The Swept Surface (2 Curves) Command will create one surface, by sweeping the firstedge curve along and in the direction of the second curve.

When the two curves are selected you are asked whether to rotate the sections along thesweep of curve. The tighter the arcs in the curve of sweep the bigger the effect of rotatingthe curve being swept.

Example Geometries Non Rotated Edge Rotated Edge Both

If the Curve of sweep is a straight line then the resultant surface is the same.

The major error that occurs with sweptsurfaces is when the starting section islonger than the internal radius on thecurve of sweep. this causes the edge tofold over its self.

Swept Surface (2 Curves) ExampleUsing the training example produce thesurface opposite.

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Curve ofSweep

Starting Section

Licom Systems Ltd.3D Surface CreationSwept Surface (3 Curves)The Swept Surface (3 Curves) Command will create one surface, by sweeping the firstedge curve along and in the direction of a second curve whilst changing into the thirdedge curve.

When the curves are selected you are asked whether to rotate the sections along thesweep of curve. The tighter the arcs in the curve of sweep the bigger the effect of rotatingthe curve being swept.

The same rules that applied to Swept Surface (2 Curves) also apply to Swept Surface (3Curves)

Swept Surface (3 Curves) ExampleUsing the training example produce the surface opposite.

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Licom Systems Ltd.3D Surface CreationRevolved SurfaceA Revolved Surface is generated by rotating a profile around an axial line.

The geometry profile MUST NOT cross the axial line.

Revolved Surface ExampleUsing the training example produce the surface opposite.

Rotation DirectionThe rotation direction will depends upon which axis X Y of Z the axial line lies in.

If the axial line has some X axis movement on it, you view down the line in the X - ve direction and + ve rotation is CCW.

If the axial line has no X axis movement then you view down the line in the Y + ve direction and + ve rotation is CCW.

If the axial line has no X or Y axis movement then you view down the linein the Z - ve direction and + ve rotation is CCW.

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Y

X

Licom Systems Ltd.3D Surface CreationCoons PatchA Coons Patch is a surface which is subtended between 3 or 4 edges. The edges can be indifferent planes but their ends MUST be coincident.

Coons patch 3 Curves is created differently to the other surface creation methods, in thatall other cases create parameter lines parallel to the edges. However it is not possible tomake the 2 parameter lines parallel to 3 edges. A coons patch 3 curves creates itsparameter lines radiating between edges 1 and 3 and parallel to edge 2.

Coons Patch 3 and 4 Curves ExampleUsing the training example produce the surfaces opposite.

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Edge 3

Edge 1

Edge 2

Licom Systems Ltd.3D Surface CreationFillet 2 SurfacesThe Fillet 2 Surfaces command will generate a fillet rad between two surface.

The fillet is always positioned between the GREY (Top) sides of the surfaces.

If the Surfaces to which the fillet is to be applied are closed then the Start and End filletradius MUST be the same.

If the Surfaces to which the fillet is to be applied are open then the Start and End filletradius can be different creating a tapered fillet. The surface extending past the fillet surfaceis deleted.

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Licom Systems Ltd.3D Surface Creation

Surface from SectionsThis command will create a surface from a minimum of 6 sectional geometry profiles.

The Sections must have their direction all to be the same.

If the sections are close the start points should be perpendicular to each other.

Surface From Sections Example.Using the training example produce the surface opposite.

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Licom Systems Ltd.3D Surface Creation

3D Surface Editing CommandsThe 3D | Edit Surface sub menu provides the following surface editing commands.

Break Intersecting SurfacesThis works in a similar manor to the Fillet between 2 Surfaces command where the 2intersecting surfaces are broken and made into 4 separate surfaces. This command will not work if the 2 surfaces do not make 4 independent surfaces.

Edit Surface Control PointsThis command will display the control points on the surface and allow one to be selectedand distorted along its vertex constrained by the surrounding control points. Thiscommand allows you to push and pull the surface skin about.

Un-Trim SurfacesThis will return a trimmed surface to its original form prior to being trimmed.

Extend SurfaceThis command will produce extra surfaces extending a set distance from either a pickedsurface edge or all 4 edges of a surface. Extend will only extend non trimmed surfaces.

Surface Finder.This command is used to separate inner and outer skinned surface models. The user isasked to pick a point in 3D space and the command will separate all the surfaces that canbe seen from that point onto a separate layer. The command may be executed fromdifferent points in order to separate the required surfaces.

Extract Edges from SurfacesThis command will work its way around the outer edges of adjoining surfaces producing acontinuous polyline.. Used with surface Finder to produce a 5 Axis Trim Edge.

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Licom Systems Ltd.3D Surface CreationConvert to STL FacetsThis converts surfaces to stl facets. Within AlphaCAM we cannot modify imported stlmodels. Additional surfaces can be used to create the additional features. These surfacesthen can be converted to stl facets so the model and be machined fully using SolidMachining..

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