DeskArtes
Rapid Tools
Update Manual
for the release of DeskArtes v. 4.0.7, July 1998.
Copyright
© 1997-1998 DeskArtes Oy. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form by any means without the written permission of DeskArtes Oy.
DeskArtes Oy reserves the right to revise this publication and to make changes from time to time without the obligation to notify any person of such revisions and changes.
Trade Marks
DeskArtes and the DA symbol are trademarks of DeskArtes Oy. Other brand and product names are trademarks and registered trademarks of their respective owners.
Address
DeskArtes Oy Kalevankatu 3 A
|
Tel. +358–9–644335 E-mail: DA@deskartes.fiURL: http://www.deskartes.fi |
Foreword
*Version 4.0.7
*General Improvements
*Refresh buttons simplified
*RENDER Menu
*Edges drawn on shaded model
*Other Options in Dialog Boxes
*Log files
*The TRANS Menu
*The DIMENS Menu
*Faceted: Dimensions
*The DESIGN Menu
*The TOOLS Menu
*Reduce
*Voxel Offset
*Surface: Intersect single
*Surface: Intersect multiple
*Surface:
Parting Lines *Rapid Facetor
*IGES translator
*Facetor Menu
*Quick Triangulate-command
*New repair tools: surface-surface intersections
*Parting Lines
*Rapid Editor
*Speed
*Separate STL files in the Background
*Parting Lines
*Flat Areas and Excess Stock
*Separation Methods
*The Repair/Orient command
*Stretch
*Drop Gap
*Extrude
*Change Normals
*Windows NT
*Screen dumps on Windows NT
*Support for the BMP File Format
*File Window
*
This Update Manual describes the changes of the DeskArtes Rapid Tools from the release of the version 4.0.1 in June 1997 to the update 4.0.7 in July 1998.
Only those functional changes are reported which significantly change the operation or add new features to the system. Speed-ups and other performance improvements are not necessarily reported here.
Changes that relate specifically to the DeskArtes Industrial Design System are reported in a separate document.
The changes introduced with version 4.0.7, the latest version, are marked throughout the margins of the printted version of this document. The most important changes regard the ability to repair surface and STL models, and extracting parting lines.
The existing software for extracting parting lines of STL models has been enhanced, and new a function for extracting the parting lines for surface models has been released.
The choice of Single/Double buffering for the refreshing method has been removed from the Settings WIndow. Now you will simply just select between
REFR being On or Off.
This menu has been removed as its functionality has now been completely replaced with the OpenGL Shaded Mode.
The Settings Window now contains a new selection for the display mode: besides
Wirefr and Shaded, there's now a button Both. It causes triangle edges to be displayed on top of the shaded model, a kind of a "hidden line" image. This feature is particularly useful when editing triangles.Many dialog boxes included a field called
Other Options. These fields have been removed. They are shown, however, when the corresponding function is used via the File Window when applying the Rapid Process command to a file.
Different modules used to create or update different log files. The current implementation appends all logs to one file called RAPIDS.LOG. One such file exists for each directory where the system is used.
Under Windows NT, this log file is rewritten after each command.
A new command,
Move Level, moves the model to a given z-level.
Interaction with the command
DIMENSÞ Faceted Dimensions has been changed, from mouse driven functions to keyboard shortcuts. The command has also been added new functionality, in particular to display object information and to store raster images.The new functions and their shortcuts are analogous to those of
Curve Dimensions, as follows:
Command |
Effect |
Comments |
p |
point value |
(was left mouse button before) |
d |
distance |
(was middle mouse button before) |
r |
radius |
(was right mouse button before) |
a |
angle |
You must then select 3 points. By selecting a suitable set of three points, the angle between two triangles can be measured too. |
b |
bounding box |
And other object info, i.e., number of facets, extents, center, area, volume |
w |
write |
Exit storing raster image to file |
q |
quit |
Exit without storing image |
Changes in Csrf.c where made. In particular, buffer_to_poly and create_surf_prim where modified, in addition to the Tolerance command. The changes are marked with ADO 4.0.7.
The handling of tolerances has been simplified. The tolerance which is displayed with the Tolerance command is now the same as the triangulation tolerance used in the Facetor menu.
Therefore, changing the triangulation tolerance in this menu will affect the tolerance used in Facetor menu, and vice-versa.
In addition, a tolerance is no longer displayed when a primitive is constructed. That tolerance it uses is the same as the tolerance displayed by the Tolerance command.
Previous implementations used a built-in tolerance for the maximum edge length of the STL models built using this menu. The program will now use the maximum edge length that has been specified in the Facetor menu instead.
Therefore, changing the maximum edge length tolerance in the Facetor menu may have an effect on the STL models designed using this menu.
Improvements have been made concerning the quality of the result.
This command invokes the Rapid Shelling software for creating hollow parts or adding excess stock to a part.
In many situations, it is a better alternative to the Rapid Offsetter because it works in a turnkey fashion, i.e. the checking and manual correction of some difficult offset cases can now be avoided. These two packages are complementary, the Rapid Offsetter excels with small offset values, the Rapid Shelling excels with large offset values and poor quality input.
The following sections describe how to use it and a comparison with the Rapid Offsetter is made so that you can more easily decide which one to use.
The requires three parameters:
• Minimum offset distance
This is the closest the offset will be from the original model.
• Offset tolerance
This value determines how much the offset can deviate, on average, from the minimum offset distance. It also determines the speed at which the result is computed. Offsets at very small tolerances may take a long time to compute. Typically, you should use a tolerance that equals half of the offset distance.
• Side
You must choose sides for the offset: inside, outside, or both. If the offset is placed inside, a hollow part can be obtained. Offsets towards the outside may be of interest when the part must have excess stock.
An offset on both sides is useful when the input data is of poor quality. For instance, it may contain gaps or too many features which make it difficult, or even impossible, for a software program to separate automatically the inside from the outside.
The result of this command is an object that represents the additional triangles. A hollow part, for instance, is the combination of the input model plus the results given by Rapid Shelling when the offset is made towards the inside. While the normals of the result will be correct when both are combined, the normals of the input model remain as they are.
Shelling In The Background
You can also invoke the Rapid Shelling on a file in a similar fashion. From the File Window, select
Rapid Process from the File List Menu. From the dialogue box that appears next, select Tools. Finally, select Voxel Offset in the same way you would from the Menu Bar.The Rapid Shelling will perform its task on the file and when it completes, a note will be displayed on your screen. In the meantime, you can use the Graphical User Interface for other tasks.
Rapid Shelling vs. Rapid Offsetter
Rapid Shelling |
Rapid Offsetter |
Can be used to offset a model that represents a closed volume. |
Can also be used to convert open, non-solid models to solid models. |
The input data does not need to be perfect, defect-free. If the problem areas are small compared to the tolerance, they have no impact on the result. |
Gaps and other defects such as self-intersections are reproduced in the result to the extent that either the input model must be repaired first, or then the result must be repaired once it is ready. |
The offset distance does not affect the quality of the result. |
The quality of the result is better with small offset distances. |
The normals of the result are automatically oriented even if the normals of the input are not correct. |
The result may need additional repair work. The minimum requirement is that the normals be oriented using the Rapid Editor. |
Computation time increases as the tolerance decreases. The offset tolerance has more impact on computation time than the number of triangles. |
Computation time is affected most by the number of triangles. |
Consequently, when choosing between these two alternatives, you must take into consideration the quality of the input data, the offset accuracy and computation time. Since computation times can vary significantly from one computer to another, it is impossible to provide hard numbers.
If the input model is an open model and the purpose is to make a solid, then the only alternative is, of course, to use the Rapid Offsetter.
The Rapid Shelling is the best alternative when either the input data has defects or the offset tolerance is relatively large. Typically, any offset distance that can be computed with a tolerance of 1mm is a suitable problem for the Rapid Shelling. It is also preferable to use it whenever you wish to minimise the amount of checking and manual work required for the offset.
Otherwise, the Rapid Offsetter is the best alternative when offsets at small distances must be computed quickly. For relatively small values, it computes the result much faster than the Rapid Shelling.
Applications
The main application area of the new shelling software is when a hollow part must be manufactured. The following sections provide guidelines for specific processes.
Hollow parts with DTM's TrueForm
The purpose of making hollow parts with this process is to improve the accuracy of the part. For this purpose, DTM recommends a wall thickness in the range of 0.75 to 1.0mm. Using a minimum offset distance of 0.8mm and a tolerance of 0.4mm results in a wall thickness in the range of 0.8 and 1.2mm.
We recommend that you check these values with DTM or their local distributor since they may change with new process/material developments.
Hollow parts with Stereolithography (SL)
The major benefit of manufacturing hollow parts with Stereolithography is the significant reduction in build times that can be achieved. In these cases, wall thicknesses greater than 2mm are desirable and the accuracy does not need to be high. A tolerance of 1 to 2mm is adequate for most applications.
However, it is necessary to create draining holes so the trapped resin can be removed. Although Rapid Shelling does not even require that the normals of the input model be oriented, you must orient the normals of the shelled part before using the Rapid Boolean to create the holes.
Hollow parts with EOS' Sintering processes
The Rapid Shelling can and should be used whenever Skin&Core fails. Since the Rapid Shelling operates in 3D, the volume reduction is more effective. Besides, Rapid Shelling has no limitations regarding wall thickness and is less sensitive to the quality of the input data.
This command computes the intersection between two surfaces.
If the resulting intersection curves delimit a closed area of the surface, that area is removed (trimmed away) from the surface.
One of the intersecting surfaces (called "this surface" in the command's terminology) is chosen for target object. After giving the
Intersect Surface command, the "other surface" is shown by pointing with the mouse.Sometimes it may be difficult to point exactly at the other surface you want. The alternative way is to click any key on the keyboard instead of pointing. You are then asked in a dialogue box the name of the element where the surface and its position within the element.
After the other surface has been shown, the program computes the intersection, and shows which part of the surfaces were cut away. The user can now tell that wrong parts were cut, and invert the result of one or the other surface. (The same could also later be done with the command
FACETORÞ Surface: Invert Cut.)If you intersect a previously trimmed surface, the system automatically combines the new trim curves with the old ones, i.e., it merges the trim sets.
The basic rule for the automatic combining of trimmings is that new trim commands always cut parts away of the old model, never adding anything. However, sometimes you may need to add parts to an already trimmed model. For this, first invert the surface's cut part, then cut away what you actually wish to add. This results in the surface part you don't want to keep. Finally invert the whole result to obtain the part you want.
Combining of Intersections
Whenever you trim (intersect or blend) a surface that has already been trimmed, the new cut is automatically combined with the old ones. The next image shows the result of two intersection operations merged together.
The corresponding trim curves are also stored separately as so-called history sets. These are located after the actual tri sets, and marked as "
..TRIM" in the Object Window. The history sets can be used if you later need to undo an old trimming.This command cuts the target surface with all other surfaces which are shown on the screen.
The command first displays the normals of the target surface, and asks whether the parts to be kept of the other surfaces are in the normal direction, or the opposite.
Just like pairwise surface intersections, the command automatically merges the trim curves with the previously existing trim curves on all surfaces.
Parting LinesThis new command cuts a surface or surfaces in an element at the parting line(s) of the surface. The surface(s) are split into two pieces, one where all surface normals are pointing downwards, and another one with normals up. Additionally, the 3D parting line is generated.
The program asks as parameters the computation tolerance ("normal tolerance"), as well as the joining accuracy for the resulting 3D parting line pieces. Small normal tolerance gives accurate results, while a large joining accuracy may help the system to better construct the 3D parting line.
As the third parameter the system asks, whether just the top or bottom part of the surfaces should be kept, or both.
In order for the system to recognize the top and bottom parts, the normal directions of the surfaces must be oriented consistently inside or outside to the model. This may most conveniently be done using command
EDITORÞ Faceted: Change Normals for each inverted surface, using the single sided shading mode.The command will have trouble computing the parting line if there are vertical walls in the model, even small ones. In such cases, the resulting parting line will typically not cut out anything of the model (result being an open trim curve).
The system colors the result surfaces which were processed without problems as blue, or green. Surfaces with non-closed parting lines are colored yellow. Surfaces with other problems are colored red.
The new release has a better IGES translator. All IGES files from any CAD system should now be translated correctly.
In addition, it has been tailored to repair automatically IGES files from CAD systems which use the IGES standard in special ways, eg. CAD systems from CATIA, Unigraphics, and ComputerVision.
For this purpose, the option
recompute all trim curves behaves differently when the default option (NO) is used. In this case, the system will take into account the CAD system which generated the file. Using this information, some or all trimming curves will be recomputed even if they are present in the input file.This simplifies considerably the handling of IGES files since the likelyhood that the file will be processed correctly the first time is greatly increased.
The order of the menu entries has been modified. The commands that verify the trimming curves are now below the ones that triangulate the model.
Quick triangulate command has been added to FACETOR menu for fast surface triangulation. This command takes each surface in the model separately and triangulates them. Thus the face boundaries are not connected, i.e. the model will not be solid. If a solid STL-model is required, the old command
Triangulate should be used.The command
EDITORÞ Faceted: Repair/Orient can be used to close the gaps in the model if Quick Triangulate is used. The gaps are closed using move vertices gap fill method.New repair tools: surface-surface intersections
Usually, the entire model cannot be built of just one surface. Instead, it is better to build the model of several surfaces and join them together by intersecting them.
Sometimes an IGES or VDAFS file may contain a surface model that includes surfaces which have not yet been intersected.
Two new commands, Intersect Single and Intersect Multiple, compute the intersection between one or more surfaces. These commands are very powerfull when repairing bad surface models before they are triangulated or sliced.
Since they are placed under the TOOLS menu, a more detailed description is found elsewhere.
It is now possible to compute the parting lines of a surface model. The current implementation does not work the same way as the parting line generation for STL models. Future implementations will be the same.
Since they are placed under the TOOLS menu, their description is found elsewhere.
All commands that operate on STL files should be faster than before, particularly the parting lines (see bellow).
Separate STL files in the Background
The command
EDITORÞ Faceted:Separate can now be invoked on a file from the File Window. Simply select a file, select the Rapid Process menu option, and then choose the Editor option from the dialog box that appears next.
The current implementation is now under the Tooling command and it takes as argument a tolerance for the draft angle. Only three objects are now created, one for each category of triangles, namely up-facing, down-facing, and vertical triangles.
If the vertical set of triangles is empty, then the model has draft.
For the sake of speed, the parting line is not given as a curve element like before. The curve must be obtained by placing the objects in separate elements and then using the Verify option in the Editor.
Flat areas can now be isolated using a new separation method available under the Tooling command. Flat areas can then be extruded in the normal direction to create excess stock or to create proper intersections to that Boolean operations will produce the desired effect.
Before separating a flat area, you must first select a triangle using the Triangle Get command in the Editor menu.
See the description of the Extrude command below.
Several new separation methods are available, in addition the connected components:
The Tooling command has additional separation methods that are related to that application area.
The option for separating offending areas collects the triangles around the gaps in a separate object. And it will collect the triangles that neighbour those around the gaps in a separate object too.
Similarly, if
misc areas are found, the triangles surrounding these areas and their neighbours are collected in two separate objects.If a triangle is both adjacent to a gap and to a misc area, it will be reported only once in the offending-related object.
Concerning offending (misc) triangles, their area can be minimized automatically using the option
minimize offending area.Since deleting offending triangles and filling the associated gap is a frequently used method for repairing such problems, this new option helps preserve as much as possible the original geometry.
A model can now be deformed by stretching it at a given X/Y/Z location and by a given amount.
First, you choose the direction, X/Y/Z. Next, a dialog box is shown and you must fill in the location and the distance. Try it, for instance, with a sphere at the origin.
This command must be applied to a 3D curve. It is meant to be used in association with the gap curves reported by the Editor.
It extrudes the curve down to a given z-level, ie. it creates vertical walls. This is usefull when designing molds from parts. First the parting lines split the part in different regions, the boundaries of these regions are extracted using the Editor, and then the vertical walls are created.
This command must be applied to a Faceted, STL object. Unlike the Drop Gap command, it extrudes the triangles by a given amount in the normal direction.
This is a very effective way to add stock to flat areas. Flat areas can now be easily manipulated using the new separation tools (see above). This command, however, can also be used with non-flat areas. In this case, the average normal direction is used.
This command was previously called Show Normals. A new command for changing the normal of single triangle has also been implemented and it can be found further down in the menu.
Incidently, the same command for Faceted objects works for surfaces too.
On Windows NT, wireframe pictures can now be printed directly using the
VIEWÞ Print command. A dialog box is displayed to select the printer and other parameters.Printing shaded images must be done differently. The image must be stored in a file first and then converted to a suitable format such as BMP (see bellow). You can also use the
PrintScreen key to place an entire window in the cut buffer, and then paste it into a program such as Paint.
Support for the BMP File Format
Using the File Window, it is possible to convert RGB files to BMP and vice-versa. Select the file and then use the
CONVERT option from the File List Menu.
The menu associated to the left-most list has an additional entry called
"My Computer". This option will list the drives in your computer. The list does not include the Network Neighbourhood, but using the Explorer you can associate a drive to a path in the network.