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This site is the source for the HawsEDC Free Software (see license below) tools, including the vehicle turning/weaving simulation program, TURN.LSP/TURNPLUS.LSP. This site also has an AutoCAD drawing with turning templates for some AASHTO vehicles (see link below). I invite you to try out any of the tools here that interest you and to tell others if you find the tools valuable.
We receive frequent feedback, and all of it is valuable; please keep it coming. Many people find TURN.LSP extremely useful, while others have some difficulty. Stephen Hitchcox and I continue to work to address the concerns of all users, and we welcome assistance in any form.
WANTED!!! Standard (like AASHTO) vehicle blocks created using TURN's BuildVehicle. Please e-mail us so we can post a library of standard vehicles. Thanks.
The use of Free Software (see gnu.org) is governed by a strong copyright called "copylefting". You can't put it into a proprietary product. You may freely make money from it by service or sale. You may modify it. But you must always allow others to copy, modify, and distribute it, including your modifications.
When you need to model a vehicle weaving through a site, a roundabout, or another geometric feature, you need a vehicle tracking program like TURN.LSP. TURN.LSP follows the polyline front axle path of a turning/weaving vehicle, inserts a vehicle block along the theoretical tracking path, and draws a polyline representing the rear axle path of the vehicle in AutoCAD. TURN.LSP is theoretically precise when use to model the centerline of front-steered wide-axle vehicles with differentials (or two-wheel bicycle-type vehicles), and its tested results correlate very well to published AASHTO turning templates, even for articulated vehicles.
Since this version of TURN.LSP has no default vehicle information, it works equally well with any vehicle. Articulated vehicles require drawing a successive path for each vehicle segment.
At minimum, all TURN.LSP needs from you is a front axle path polyline and a back axle starting point. Try the following exercise.
First, draw a good, long, polyline representing a front axle path. For good looks, begin and end the path with plenty of straight length. then (just for convenience and clarity, not necessity) offset the polyline half the vehicle width to create the wheel paths.
Second, draw the theoretical axles. Draw a line between the two starting points of the front wheel paths for the front axle, then offset the line back the wheelbase length to make the back axle. If you want to try modeling an articulated vehicle, offset the first back axle to the articulation hinge, and offset another line to the next axle back.
Third, load and run TURN.LSP by dragging it into your drawing and typing TURN. When prompted, select near the beginning of a polyline that represents the path of the front axle centerline at the initial front axle middle location. Then use osnaps to select the exact point representing the middle of the back axle. TURN.LSP uses this point to calculate wheelbase length and initial vehicle orientation. Then accept TURN.LSP's suggestions for a calculation step and plotting accuracy or enter your own. Finally, enter the name of a block that represents the outline of the vehicle or vehicle segment you are modelling.
TURN.LSP draws several POINT objects, then erases them and draws the path of the back axle. Then TURN.LSP inserts the vehicle block along the modelled path.
If you are modeling an articulated vehicle, run TURN again by typing TURN, then select the newest turning path as the front axle path. the next axle back as the back axle (use your osnaps), and enter the block name of the next segment.
Notes about blocks:
For a proper vehicle block definition, the front points to 0 degrees and the insertion point is at the point that determines tracking. For a single segment vehicle or a front vehicle, the insertion point is the middle of the front axle. For subsequent segments, the insertion point is likely the hitch location.
| Vehicle | Width | WB1 | WB2 | Min. Outside Radius | Min. Inside Radius (check) |
|---|---|---|---|---|---|
| P (passenger) | 7 | 11 | 24.0 | 13.8 | |
| SU (single truck) | 8.5 | 20 | 42.0 | 27.8 | |
| BUS | 8.5 | 25 | 42.0 | 24.4 | |
| WB-40 | 8.5 | 13 | 27 | 40.0 | 18.9 |
| WB-50 | 8.5 | 20 | 30 | 45.0 | 19.2 |
Vehicle defaults might be added to TURN.LSP without much difficulty with enough interest or funding.
| Date | Programmer | Revision |
|---|---|---|
| 20070122 | TGH | 1.0.4 Added block plotting. Made code more modular with defined data structure. |
| 20061216 | TGH | 1.0.3 Replaced GETDISTX with originally written version. |
| 20061213 | TGH | 1.0.2 Clarified prompts, changed pline reversal criteria, added undo group. |
| 20020625 | TGH | 1.0.1 Added capability to follow reverse drawn polylines. |
| 20020627 | TGH | Added GETDISTX function to distribution file. |
| 20021025 | TGH | Replaced tracking equation with better algorithm. Removed plot point reduction algorithm. |
To submit revisions, send an email with your revised code.
This program is free software under the terms of the GNU (GNU--acronym for Gnu's Not Unix--sounds like canoe) General Public License as published by the Free Software Foundation, version 2 of the License.
You can redistribute this software for any fee or no fee and/or modify it in any way, but it and ANY MODIFICATIONS OR DERIVATIONS continue to be governed by the license, which protects the perpetual availability of the software for free distribution and modification.
If you improve this software, make a revision submittal to the copyright owner. See www.hawsedc.com.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License on the World Wide Web for more details.