Win32 and 64, English

The application for modeling curves and surfaces of high quality on criteria of smoothness.

General Usage Instructions

Command V_Model is the basic command of Application. The Command creates fair curves and surfaces. The command has a complicated structure of options using the string menu. The specific set of options depends on the selected object:

1) 3D Polyline – is used to edit and create fair v-curve and to approximate created v-curve by rational Bezier spline (NURBzS) curve. 3D Polyline can be used as a base polyline or as a tangent polyline and can be used directly as s-polygon of b-spline curve. You can edit v-curve on a base polyline or on a tangent polyline and NURBS curve on s-polygon with testing the quality of the curve by the graphs of curvature and evolute and by the values of macroparameters of the curve type values of the potential energy of the curve, values of the minimum and maximum curvature. Options

2) Set of 3D Polylines – is used to unite 3D Polylines to 3D Mesh. Options

3) NURBzS curve (created on 3D Polyline) – is standard form of presentation of spline in Autodesk® AutoCAD®. NURBzS curve can be approximated by rational b-spline (NURBS) curve of high degree m (m = 6/8/10). Options

4) NURBS curve (directly created on 3D Polyline as on s-polygon or created on the NURBzS curve) - is standard form of presentation of spline in AutoCAD. NURBS curve can be edited by s-polygon with testing of quality on graphics of curvature and evolute. Options

5) 3D Mesh – is used:

- To create network of fair v-curves on rows and columns of 3D Mesh and create on them a rational spline Bezier surface of degrees (3,3) (NURBzS surface);

- To create forming fair v-curves on rows and approximate by b-spline curves, then to create the directing b-spline curves on columns of 3D Mesh of s-polygons of forming b-spline curves. And on frame of directing b-spline curves to create b-spline surface (NURBS surface). Options

6) Set of NURBzS curves – is used to unite curves to the frame of forming curves of NURBzS surface and then to create NURBzS surface or NURBS surface. Options

7) Set of NURBS curves is used to unite b-spline curves to the frame of forming curves of NURBS surface and then to create on columns of 3D Mesh of s-polygons of forming b-spline curves the directing b-spline curves. And on frame of directing b-spline curves to create b-spline surface (NURBS surface). Options

8) NURBzS and NURBS surfaces (created in Application). You can test the quality of the surface, edit the b-spline surface, create the parallel surfaces, change format of representation of the surface and pull out patches of the surface. To enter the surfaces of Application into the primitives of AutoCAD the NURBzS and NURBS surfaces of Application can be approximated by primitive 'Lofted Surface' of AutoCAD or can be converted geometrically exactly through IGS-format to NURBS surface of AutoCAD. You can edit the b-spline surface by s-frame with testing of quality and with control form of any isoparametric curve. Options

Two add commands (V_Clothoid, V_Hermite) are intended for modeling French Curves on base of analytic curves. When designing the products with functional curves it is often necessary to use curves with specific properties: a catenary for modeling the domes or hanging constructions; a line of steepest descent for time synchronization of motion of particles under the action of gravity from any point of the curve to the end point; Cornu spiral (or clothoid) with a linear change of curvature for tracing roads; etc. The application allows the use of various analytic curves. Options



Ribbon/Toolbar Icon Command Command Description


Basic command of Application. Command creates fair curves and surfaces.


Approximates an analytic curve set by the table of coordinates of points, tangents and curvature.


Updates the Code Activation. Before executing the command, download Activation Code.


The command is executed for the correct completion of the Application. Unloads the objectARX. Deletes temp-files.


Creates site of Clothoid.


The installer that ran when you downloaded this app/plug-in from Autodesk App Store will start installing the app/plug-in. OR, simply double-click the downloaded installer to install the app/plugin. You may need to restart the Autodesk product to activate the app/plug-in. To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button. OR, click Control Panel > Programs > Programs and Features (Windows 7/8/8.1/10) and uninstall as you would any other application from your system.

At the first start or completion of the term of the license Application executes the command V_Reset. The command displays a message offering to download on the Web Service Register3D your activation code. 

Go to the Web service, read the license agreement and log in with your email address and UserId. After registering, click [to Download the Code of Activation]. On the page 'CodeActivation3D' click [Download]. Web service displays the text of the activation code. Right click in the text area and then click the option to save the file. Save the file 'Code_Activation.txt' on your computer.

Additional Information

Scientific and program development presented on the site of authors: http://spliner.ru

Authors are ready according your requirements or your technical project to perform the development of specialized applications based on FairCurveModeler for designing the objects with functional curves and surfaces:

- For the tracing and profiling roads

- For design of cam mechanisms

- For design work surfaces of tillage machines

- For design of outer surfaces of ships, aircraft, automobiles, architectural objects.



The maximum number of vertices of the initial polyline - 128.

When constructing base polyline follow strict restrictions on the form of polyline:

-The angles between adjacent segments must be greater than 90 degrees.

-Closed polyline is defined by at least 5 points / lines.

-Unсlosed polyline is defined by not less than 3 points / lines.

-Locally convex parts of polyline with points / lines of inflection are defined by not less than 4 points / lines.

-The inflection point of curve is defined by the midpoint of two segmented part that divides a polyline into sites with different signs of orientation of form of polyline. This two segmented part must have a smaller angle than the adjacent two segmented parts (in particular midpoint of two segmented part can lie on a straight line).

-Straight site of curve defined by 3 and more vertices strictly on the line.

When you specify a tangent polyline, an imaginary polyline that passes through the middles of links of tangent polyline must satisfy these strict restrictions.

When setting the fixed values of the curvature at the end points of the curve at approximation by b-spline curve [BSpline] the values of the curvature must be smaller (and values of the radii larger) than the values of curvatures (values of radii), which are determined by default.

At approximation of v-curve by a b-spline curve of degree 8 on critical sections of polyline (sections with an abrupt change of curvature, transitions to the straightness) approximation error may be greater than a predetermined (0.000001). In this case, the application displays a warning.

Known Issues

Previously learn description of the commands. Test the application using the library of scripts in the folder Examples. Scripts demonstrate the functionality of the application. Use the scripts for training to work with the application. Use scripts to work with your data by replacing the initial data in scripts.

If a command of the construction of the curve does not complete, it is possible that you have not registered the program SModeller.exe, since the start AutoCAD in the first execution of the Application is not as the administrator. Enter the Application folder ./Contents/Windows and run SModeller.exe as administrator.

If the program displays a message that the 'Code Activation' need to update, it means that the license validity period has ended. Buy in Apps Exchange monthly or annual license and resubmit the command v_install.


Company Name: RespectSoft
Support Contact: geometry@respectsoft.ru

Author/Company Information


Support Information

Version History

Version Number Version Description


In this version 1) The algorithm for constructing the b-spline curve is improved. The b-spline curve preserves the direction of the tangent at the point of inflection of the original curve; 2) In the construction of the b-spline curve with fixed values ​​of curvature, the curvature changes smoothly; 3) The functionality of the V_Hermite command is extended. You can create NURBS-templates of Clothoid, SuperSpiral, Involute, Conical Spiral, and NURBS-template of any curve specified by the Hermite GD table; 4) The functionality of the program is expanded when constructing a curve on a polyline with a small number of segment


Initial release
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