# Timber NC-operations - Background & general modelling aspects

Construsoft developed and implemented several Timber NC-export tools in Tekla Structures.

Each of these export tools is dedicated to a specific Timber NC-file format, each with their own scope and definition.

The scope of some of the formats is such that Tekla can unambiguously determine the operation from the geometric information. These are categorized as basic formats. There are however also formats for which, for volumetric operations, it is not possible to unambiguously determine which operation is meant. In those cases the user needs to provide additional non-geometrical information in the form of the name of the operation. These file formats are categorized as advanced formats.

Another way to categorize the file formats is by considering the type of objects they can describe.

Next table illustrates these categorizations:

Single-piece |
Framing |
||||

Timber NC-File format |
Type |
Beam |
Plate |
Beam |
Plate |

BTL |
Advanced | Yes | Yes | Yes | Yes |

Hundegger-BVN (K2) |
Advanced | Yes | No | No | No |

Hundegger-BVX (SC3) |
Advanced | Yes | No | No | No |

Hundegger-BVX2 |
Advanced | No | Yes | No | No |

GT_Hechttechniek |
Basic | No | No | Yes | Yes |

HM (M311 ; HMT ; HMZ) |
Basic | Yes | No | No | No |

Randek |
Basic | No | No | Yes | Yes |

Tigerstop |
Basic | Yes | No | No | No |

This document is meant for end-users that want to model and export single parts to any of the advanced file formats. It is not a manual on how to apply the related Timber NC-Export tool. Instead, it aims to provide handles that will help the end-user to model in such a way that the export to the chosen advanced Timber NC-file format can be performed without problems.

Not every operation can be described by all advanced file formats. This document handles the direct sum of available operations that are available in the several advanced file formats.

As a final remark, this document does not pretend to be complete with regard to all details, properties and scope of all operations of each one of these advanced file formats.

For a full description, please review the official document(s) from the developers of the format.

### 1. Categorization of Timber NC-operations

The most coarse way is to categorize an operation as:

A. Changes geometry of a part

B. Does not change geometry of a part

Operations that change geometry of a part can be subdivided in operations that are:

A.1 Separating

A.2 Profiling

A.3 Discrete

Operations that do not change geometry of a part are in general denoted as Annotation operations such as

B.1 Marking

B.2 Text

This categorization of a Timber NC-Operation can be depicted as:

### A. Operations that change geometry

### A.1 Separating Timber NC-operations

Note that one of these operations is planar, all others are volumetric.

In the advanced Timber NC-file formats, the negative volumes that model the volumetric operations must be given the appropriate name.

Note that for certain cases a combination of negative volumes may be necessary to achieve the required result. Each of those negative volumes must have proper shape and name.

### A.2 Profiling Timber NC-operations

.

When a non-profiled part is subjected to a profiling operation it renders that part profiled.

A profiling operation has the following properties:

• The system line of the operation is parallel to the system line of the part it operates on

• The operation stretches throughout (at least) the complete length of the part it operates on

Note that all profiling operations are volumetric.

In the advanced Timber NC-file formats, the negative volumes that model the volumetric operations must be given the appropriate name.

Note that for certain cases a combination of negative volumes may be necessary to achieve the required result. Each of those negative volumes must have proper shape and name.

### A.3 Discrete Timber NC-operations

Note that, except the bolt holes generated by the Bolts command, all geometry-changing discrete operations are volumetric.

In the advanced Timber NC-file formats, the negative volumes that model the volumetric operations must be given the appropriate name.

Note that for certain cases a combination of negative volumes may be necessary to achieve the required result. Each of those negative volumes must have proper shape and name.

### B. Operations that do not change geometry

### B.1 Marking Timber NC-operations

### B.2 Text Timber NC-operations

Hence, there is no image to show.

### 2. Tekla Structures entities

C. Negative Volume

D. Plane

E. Bolt

A negative volume can be:

C.1 based on a beam object

C.2 based on a contour platepart whose outline form the user defines by picking three or more points

The user can define the shape of the contour plate parallel to the work plane. The profile in use defines the thickness. The corners of the contour plate can be chamfered.

object

C.3 based on polygon Cutcut that is defined by a polygon

A Plane can be a:

D.1 Fit-plane

D.2 Cut-plane

A bolt holesmall hollow open throughout a part or assembly that is usually used for fastening parts with bolts or other such objects

Hole is created in the same way as bolts and hole properties are defined in the bolt properties.

can be modelled using either the Bolts command or a cylindrical negative volume.

Next image provides an overview of these entities:

### C. Tekla entities – Negative volume

(*) Exception to this rule is for modelling bolt holes.

Bolt holes can be modelled using either a negative volume based on a cylindrical beam part or by applicationpart of Tekla Structures functionality that is developed in order to extend the capability of Tekla Structures but that is not included in the Tekla Structures installation

of the Bolts command.

In Tekla, a negative volume can be modelled using either:

a) Part cutcut that is defined by a cutting part

based on beam

b) Part cut based on contour plate(1) part that represents a flat structure

(1) In some contexts, for example in analysis, the term plate object may be used to refer to plates.

(2) plate that represents a steel structure

(2) Plate is mainly used as a connection piece or as a floor plate.

c) Polygon cut

The majority of volumetric operations is rectangular and prismatic.

Using a polygon cut or contour plate, the user needs to specify the location of all the vertices. Using those methods, the chance that the final result does not meet this shape restriction is quite large. Therefore it is advised to only use either of these two methods when the required result cannot be achieved by using the beam method.

In the advanced Timber NC-file formats, the negative volumes that model the volumetric operations must be given the appropriate name.

Note that for certain cases a combination of negative volumes may be necessary to achieve the required result. Each of those negative volumes must have proper shape and name.

### C.1 Negative volume-Based on Beam object

• The volume enlarges the bounding boxrectangular border with the smallest measure within which all the selected points that position the model objects lie

In Tekla Structures two-dimensional bounding boxes are used in drawings and three-dimensional bounding boxes in models.

of the virginal part in all directions that the required operation allows.

• The shape of the volume must be definable using the set of parameters that the file format defines for the operation. In general this means that the negative volume must be rectangular and prismatic.

Next images show some examples that illustrates these recommendations and restrictions.

### C.2 Negative volume-Based on contour plate object

• The volume enlarges the bounding box of the virginal part in all directions that the required operation allows.

• The shape of the volume must be definable using the set of parameters that the file format defines for the operation. In general this means that the negative volume must be rectangular and prismatic.

Furthermore it is advised to model the contour plate in such a way that the first (=yellow) point lies outside the virginal solid. This first point represents the tip of the tool on the machine and the machine cannot start the operation from within a solid.

Next images show some examples that illustrate these recommendations and restrictions.

### C.3 Negative volume-Based on polygon cut

### D. Tekla entities – Planes

.

A fit plane rotates the end face of a solid so it matches the orientation of the specified fit plane.

A cut plane actually removes a portion of the solid.

If there is only one Planar operation on an end face, Tekla Structures prescribes to use a Fit plane.

If there is more than one planar operation on an end face, Tekla Structures prescribes to first apply a Fit plane and a Cut plane for all other.

For modelling the planar timber NC-operations these same rules apply.

### E. Tekla entities – Bolt holes

In the advanced Timber NC-file formats, these cylindrical negative volumes must be given the appropriate name.

Full depth bolt holes can be modelled with the in-built Bolts command as well.