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Introduction Solids Modelling allows us to use triangulation to create three-dimensional models based on Digital Terrain Models (DTMs) and String files. This document introduces the theory behind the solids modelling process and provides detailed examples using the solids modelling functions in Surpac. By working through this manual, you will gain skills in the construction, use of and modification of solids models
Solids Modelling in Surpac 6.0 May 2007 Copyright © 2007 Gemcom Software International Inc (Gemcom) This software and documentation is proprietary to Gemcom and, except where expressly provided otherwise, does not form part of any contract Changes may be made in products or services at any time without notice Gemcom publishes this documentation for the sole use of Gemcom licensees Without written permission you may not sell, reproduce, store in a retrieval system, or transmit any part of the documentation For such permission, or to obtain extra copies please contact your local Gemcom office or visit www.gemcomsoftware.com While every precaution has been taken in the preparation of this manual, we assume no responsibility for errors or omissions Neither is any liability assumed for damage resulting from the use of the information contained herein Gemcom Software International Inc Gemcom, the Gemcom logo, combinations thereof, and Whittle, Surpac, GEMS, Minex, Gemcom InSite and PCBC are trademarks of Gemcom Software International Inc or its wholly-owned subsidiaries Contributors Rowdy Bristol Phil Jackson Kiran Kumar Product Gemcom Surpac 6.0 Table of Contents Introduction Requirements Objectives Workflow Solids Concepts Setting the Work Directory Preparing Data Creating a Solid 15 Triangulating Using Between Segments 15 Triangulating Using Control Strings 18 Triangulating Using Many Segments 22 Triangulating Using Bifurcation Techniques 24 Triangulating Using Segment to a Point 38 Triangulating a Fault 49 Triangulating Using Inside Segment and One Triangle 59 Triangulating Using Manual Triangulation 62 Editing Solids 64 Validating Solids 65 Triangulating Using Centre Line & Profile 68 Intersecting Solids and DTM Surfaces 74 Intersecting Solids 74 Intersecting DTM Surfaces 83 Viewing Solids 88 Creating Sections 91 Reporting Volumes of Solids 98 Intersecting Drill Holes with Solid Models 100 Optimising Trisolations 105 Modelling Underground Data 107 Using The Triangulation Algorithm 116 Page of 120 Introduction Solids Modelling allows us to use triangulation to create three-dimensional models based on Digital Terrain Models (DTMs) and String files This document introduces the theory behind the solids modelling process and provides detailed examples using the solids modelling functions in Surpac By working through this manual, you will gain skills in the construction, use of and modification of solids models Requirements This tutorial assumes that you have a basic knowledge of Surpac We recommend that you understand the procedures and concepts in the Introduction to Surpac manual The DTM Surfaces tutorial may also be helpful in understanding some of the concepts in this tutorial You will also need to have: • Surpac installed on your computer • The data set accompanying this tutorial Objectives The objective of this tutorial is to allow you to work with solid modelling tools It is not intended to be exhaustive in scope, but will show the work flows needed to achieve results You can then refine and add to this workflow to meet your specific requirements Page of 120 Introduction Workflow Workflow Start Create/Edit String data Triangulate No Validate Valid? Yes Set to solid Save Finish Page of 120 Solids Concepts Workflow Solids Concepts What is a Solid model? A Solid model is a three-dimensional triangulation of data For example, a solid object may be formed by wrapping a DTM around strings representing sections through the solids Solid models are based on the same principles as Digital Terrain Models (DTMs) Solid models use triangles to link polygonal shapes together to define a solid object or a void The resulting shapes may be used for: • • • • visualisation volume calculations extraction of slices in any orientation intersection with data from the geological database module A DTM is used to define a surface Creating a DTM is automatic Triangles are formed by connecting groups of three data points together by taking their spatial location in the X - Y plane into account The drawback of this type of model is that it cannot model a structure that may have foldbacks or overhangs, for example: • • • geological structure stopes underground mine workings, for example: declines, development drives and draw points A Solid model is created by forming a set of triangles from the points contained in the string These triangles may overlap when viewed in plan, but not overlap or intersect when the third dimension is considered The triangles in a solid model may completely enclose a structure Creation of Solid models can be more interactive than the creation of DTMs, although there are many tools in Surpac that can automate the process Page of 120 Solids Concepts Workflow The following diagram shows an example of a Solid model (design decline and ore body) Terminology A Solid model is made up of a set of non-overlapping triangles These triangles form objects that may have a numeric identifier between and 32000 Objects represent discrete features in a solid model For example, in the above diagram, the decline and the ore bodies have different object numbers since they represent different features However, features such as ore bodies can consist of discrete pods, and you may want to give these pods the same object number to indicate that they are from the same structure In this case, each discrete pod must have a different trisolation number A trisolation is a discrete part of an object and may be any positive integer Object and Trisolation numbers give reference to all the objects contained in a Solid model An object trisolation may be open or closed A trisolation is open if there is a gap in the set of triangles that make up the trisolation An object may contain both open and closed trisolations The reason for treating objects as open or closed are: • • • • a closed object can have its volume determined directly by summing the volumes of each of the triangles to an arbitrary datum plane a closed object always produces closed strings when sliced by a plane a closed object could be used as a constraint in the Block Modelling module an open object cannot provide the same capabilities; when sliced by a plane the strings it produces may be open or closed or both Solids Files Solid models are stored in the same way that DTMs are stored, in two ASCII text files, with str and dtm extensions Detailed notes and examples of string and DTM file formats can be found in the Online Help Manual under Appendix D - File Formats Page of 120 Setting the Work Directory Workflow Setting the Work Directory A work directory is the default directory for saving Surpac files Files used in this tutorial are stored in the folder: \demo_data\tutorials\solids where is the directory in which Surpac was installed Task: Setting the Work Directory In the Surpac Navigator, right-click the solids folder From the popup menu, select Set as work directory The name of the work directory is displayed in the title bar of the Surpac window Page of 120 Preparing Data Workflow Preparing Data Overview Spending a few minutes checking the integrity of strings prior to beginning modelling will help to ensure trouble free model creation This chapter will give you a few pointers on how this is done in Surpac This chapter will show you how to check for: • • • • string direction foldbacks (also called spikes) excessive number of points duplicate points String Direction Strings should all be in the same direction, even if they are open strings For example, you should not have the following situation: In this case, you should reverse the direction of string Foldbacks Foldbacks or spikes in a string will cause problems with your model as they may cause overlapping triangles to be formed Large Numbers of Points Large numbers of points (ie more than necessary to define a structure) will slow model creation and you should filter strings as necessary You should also ensure that all data to be modelled is in the same coordinate system, and that the data is in a normal plan projection Having all the data in a plan projection will considerably simplify the modelling of the data Page of 120 Preparing Data Workflow Task: Combining String Files into one File Choose File Tools > Combine/Split file options > Combine string files Enter the information as shown, and then click Apply This will combine all sixteen files into one string file called ore1.str Choose File Tools > Change string directions Enter the information as shown, and then click Apply This will ensure that all digitised segments are set to clockwise This string file is a series of sectional interpretations, representing a copper ore body Page of 120 Optimising Trisolations Intersecting DTM Surfaces Optimising Trisolations Overview The Optimise function involves filtering 3D objects to reduce the number of points This has particular relevance to Cavity Monitoring System (CMS) data where there are a very large number of data points produced by the instrument All these points are typically not required for defining the shape, making memory requirements high and processing time a lot slower This function requires the input trisolation to have been validated and the object direction set The input trisolation may be open or closed In this chapter you will learn how to optimise trisolations that contain excessive triangles and remove redundant points resulting from the filtering process Task: Optimising Trisolations Click the Reset graphics icon Open filter1.dtm Choose Solids > Edit trisolation > Optimise Click the object Enter the information as shown, and then click Apply Choose Display > Strings > As lines Choose Solids > Edit trisolation > Delete redundant points Page 105 of 120 Optimising Trisolations Intersecting DTM Surfaces Click Apply on the form presented Notice that more than 90% of the points were deleted and any segments not associated with a triangle have been deleted If you want to see all of the steps performed in this task, run _13_optimise_trisolation.tcl Note: Whenever the macro pauses, displaying the prompt “Click in graphics to continue” in the message window, you will need to click in graphics Also, you will need to click Apply on any forms presented Page 106 of 120 Modelling Underground Data Intersecting DTM Surfaces Modelling Underground Data Task: Modelling Underground Data Click the Reset graphics icon Open lev200.str An oblique view of part of the file is shown: Choose Display > Strings > With string numbers Enter the information as shown, and then click Apply Note: In this case, the string numbers for the backs are and 30003 and for the floor are and 1001 String 30003 is a spot height string You will need to create separate DTM files for the backs and the floors Choose File > Save > string/DTM Page 107 of 120 Modelling Underground Data Intersecting DTM Surfaces Enter the information as shown, and then click Apply Note: This creates a string file containing just the back strings Notice that the separator for the string range is a semi colon Choose File > Save > string/DTM Enter the information as shown, and then click Apply Note: 10 This will create a string file containing just the floor strings Notice that the separator for the string range is a semi colon Click the Reset graphics icon Open back1.str Strings and 30003 are displayed 11 Choose Inquire > Segment Properties and click on each segment to check its direction Notice that the pillar segment is anti-clockwise within an enclosing outer boundary segment that is clockwise Page 108 of 120 Modelling Underground Data Intersecting DTM Surfaces 12 13 Choose Surfaces > Create a DTM from layer Enter the information as shown, and then click Apply 14 Choose Surfaces > Clip or intersect DTMs> Clip DTM with string You are prompted to select a string 15 16 Click string (ie pillar and wall pickup string) Enter the information as shown, and then click Apply You will see a clipped DTM of the backs as shown Note: The DTM has been clipped correctly due to the string directions set for the walls and pillar Page 109 of 120 Modelling Underground Data Intersecting DTM Surfaces 17 18 Choose File > Save> string/DTM Enter the information shown, and then click Apply 19 20 21 22 Click the Reset graphics icon Open floor1.str Choose Surfaces > Create DTM from layer Enter the information as shown, and then click Apply 23 Choose Surfaces > Clip or intersect DTMs > Clip DTM with string You are prompted to select a string 24 25 Click string Enter the information as shown, and then click Apply You will see a clipped DTM of the floors as shown Page 110 of 120 Modelling Underground Data 26 Save floor1.dtm 27 Click Reset graphics Intersecting DTM Surfaces Now that both clipped DTMs have been created, stitch together the sides to create a closed, validated Solid model 28 Open and append back1.dtm and floor1.dtm into the main graphics layer Note: To append the DTMs to the same layer, hold down the CTRL key and drag and drop the files into graphics 29 30 31 Choose Solids > Edit trisolation > Renumber Click back1.dtm Enter the information as shown, and then click Apply 32 33 Click floor1.dtm Enter the information as shown, and then click Apply Note: 34 35 Press ESC to terminate the function Save the file as drives1.dtm Note: 36 Notice that the old trisolation number is in this case When performing Solids modelling, it is good practice to save your work often Choose Display > Strings > With string numbers Page 111 of 120 Modelling Underground Data Intersecting DTM Surfaces 37 Enter the information as shown, and then click Apply 38 39 Choose Solids > Triangulate > Between segments Enter the information as shown, and then click Apply 40 Following the prompts from the function line, click first the outer back string, and then the outer floor string Press ESC to terminate the function 41 You must now repeat the process for the pillar 42 43 Choose Solids > Triangulate > Between segments Enter the information as shown, and then click Apply 44 Following the prompt from the function line, click first the top string of the pillar, and then the bottom string of the pillar Press ESC to terminate the function 45 Your data will look like the following: Page 112 of 120 Modelling Underground Data 46 47 48 Intersecting DTM Surfaces Save drives1.dtm Choose Solids > Validation > Validate object Enter the information as shown, and then click Apply Page 113 of 120 Modelling Underground Data Intersecting DTM Surfaces A file called valid1.not is created, which shows that there are no errors with the solid 49 50 Choose Solids > Validation > Set object to solid or void Enter the information as shown, and then click Apply 51 52 Choose Solids > Solids tools > Report volume of solids Enter the information as shown, and then click Apply Page 114 of 120 Modelling Underground Data Intersecting DTM Surfaces If you want to see all of the steps performed in this task, run _15_create_underground_model.tcl Note: Whenever the macro pauses, displaying the prompt “Click in graphics to continue” in the message window, you will need to click in graphics Also, you will need to click Apply on any forms presented Page 115 of 120 Using The Triangulation Algorithm Intersecting DTM Surfaces Using The Triangulation Algorithm Overview This section provides an explanation of the Triangulation Algorithm function and how it can be successfully applied in different circumstances Choose Solids > Triangulate > Triangulation algorithm to change the triangulate stitch algorithm while Surpac is running The stitch algorithm is the algorithm used by the Triangulate functions to create triangles to stitch segments together You will find that different stitch algorithms will give you better results in different geometric situations You have four options as shown: • • • • 0: old algorithm 1: new algorithm 2: old algorithm with transforms 3: new algorithm with transforms The default value of the option in the defaults.mst file is new algorithm with transforms Task: Use the Triangulation Algorithm Click the Reset graphics icon Open bifurc2.str Choose View > Data view options > View by bearing & dip Enter the information as shown, and then click Apply Choose Display > Strings > With string numbers Page 116 of 120 Using The Triangulation Algorithm Intersecting DTM Surfaces You will see the image as shown: Choose Solids > Triangulate > Triangulation algorithm Ensure that new algorithm with transforms is selected Choose Solids > Triangulate > Between segments Enter the information as shown, and then click Apply 10 Click string then the right hand segment of string as shown: 11 Press ESC to terminate the input Page 117 of 120 Using The Triangulation Algorithm Intersecting DTM Surfaces 12 13 14 15 Click the Reset graphics icon Open bifurc2.str Choose Solids > Triangulate > Triangulation algorithm Ensure that old algorithm with transforms is selected 16 17 Choose Solids > Triangulate > Between segments Enter the information as shown, and then click Apply 18 Click string then the right most segment of string as shown: 19 Press ESC to terminate the input Note: 20 21 22 23 The old algorithm with transforms also achieved a successful result but took significantly longer This demonstrates the principal difference between the new and old algorithms, ie the new one is much faster Click the Reset graphics icon Open bifurc2.str and choose a similar view to that used before Choose Solids > Triangulate > Triangulation algorithm Ensure that new algorithm is selected Page 118 of 120 Using The Triangulation Algorithm Intersecting DTM Surfaces 24 25 Choose Solids > Triangulate > Between segments Enter the information as shown, and then click Apply 26 Click the same segments and observe the result as shown In this case the segments are too far apart geometrically for either the old algorithms or new algorithms (options and respectively) to work and the options with transforms should be chosen in preference Finally, restore the triangulation algorithm to it original value 27 28 Choose Solids > Triangulate > Triangulation algorithm Enter the information as shown, and then click Apply If you want to see all of the steps performed in this task, run _16_triangulation_algorithm.tcl Note: When ever macro pauses, displaying “Click in graphics to continue” in the message window, you will need to click in graphics to allow the macro to continue Also, you will need to Apply the forms presented Page 119 of 120