# Autodesk Inventor Dynamic Simulation Tutorial using IN-Motion

IN-Motion is a Motion and Dynamic Simulation Addin for Autodesk Inventor. Autodesk has certified IN-Motion as a compatible addin for Inventor 2009 and 2010 versions. In this tutorial, I shall explain in brief What is Dynamic Simulation using a simple example of 2 bodies. gravityText.iam has two parts namely housing (grounded part) and bob (pendulum). We define a Mate constraint between the cylindrical sufraces of these two parts. The mate created has 2 degrees of freedom (DOF). One is relative rotation between the two parts about their common axis and relative translation about their common axis. In Kinematics, this constraint is referred to as a Cylindrical joint / pair. Now that we have our assembly ready, we go to “IN-Motion” by clicking on “Environments” ribbon tab and then “IN-Motion” as shown in the figure below. (Inventor 2009, go to Applications >> IN-Motion )

IN-Motion loads up and converts all the Inventor constraints into corresponding Kinematic joints or pairs. In this case, Mate:1 constraint is converted to a cylindrical joint. We then define the “Gravity” acting on the assembly. From the IN-Motion tab, click on “Define Gravity” and enter the value of Gravity in Y direction = “-10” m/s^2. This will make the gravity act in the downward direction with respect to the below figure.

Now, we will look briefly at what we mean by Dynamic Simulation. We can draw “free body diagram” (FBD) of pendulum bob and derive the equations of motion for it. Since only gravity is acting on it., the forces acting on it is shown in the figure below. “F” corresponds to the resultant force acting on pendulum bob. “Fr” is the reaction force between the cylindrical surfaces of both the parts and “Fj” is force acting along the axis of the joint (joint force). Their values are calculated as shown in the figure below.

Click on the “Simulation Player” button in the top panel. A dialog / form appears. Change the end-time to 0.2 seconds and click on simulate button. IN-Motion now performs mathematical analysis and shows the messages as shown in the figure below. Click on the “Playback Deck” button and you can play the animation and notice that at the end of simulation, the bob comes down due to the action of gravity, which is evident from the equations of motion.

Now, we can determine the value of reaction force by performing Dynamic Simulation using IN-Motion. Right click on Mate:1(Cylindrical) and goto “Force /Torque Graph” context menu item. A graph plot appears and upon selecting “Force” and “Magintude”, the following graph appears.

You can observe that the numerical value of Force(N) v/s Time(s) almost remains constaint (but for minor variations due to numerical methods of computation). The value can be approximated to 4.678 N and we had got same value Fr from our Mathematical Calculation (Equations of Motion).

Now, we can define the Joint Force. Right click on Mate:1(Cylindrical) node and select “Define Force”. A dialog/ form appears.

Enter the value as “-4.0” N and simulate the assembly. You would observe that the pendulum still moves down, but the resultant force acting on it has been reduced and hence its displacement at the end of simualtion is less than that under free fall. We can also test the simulation for Force = “-5.0” N. This time, the pendulum moves upwards slowly. Lets do a final check by putting the value of Force = “-4.678” N.

If you simulate the assembly now, the pendulum bob does not move at all. This is the force thats same as Fj and hence it balances the force due to gravity and hence the pendulum is in Equilibrium.

This is how IN-Motion can be used to determine characteristics of Multi body systems and then we can define appropriate forces/torques or motion to see its affect on the system.

I had recorded a screencast of the above tutorial and its embedded below. For a high clarity video, check out AR-CAD website.

Hope to bring more such tutorials in future. For some people in Dynamic Simulation domain, tutorials of this kind may be very trivial, but majority of beginners could find simple tutorials like these useful. Please comment back if there is any confusion or suggestions.

Regards,

Rajeev Lochan

# IN-Screenshot Free Addin for Autodesk Inventor

This post is for all Autodesk Inventor Users. How many times have you felt the need to take a screenshot of your Inventor file (assembly, part, drawing etc) and send it across to people who do not have Inventor or even upload the image online. You would have to follow one of the following two options

Option A: File > Save As> Save Copy As> and then select .jpg or .png as extension and save the file.

Option B: Use “Print Screen” key on your keyboard, go to MS Paint or other image editing software, paste the copied image and then save it.

It presently works on Inventor 2009 and 2010 versions and should also be able work on 2011, when it would be released. We have tested it to work on both 32 and 64 bit OS of Windows XP, Windows Vista and Windows 7.

You are free to try the addin and let us know your valuable feedback.

Disclaimer: Some days ago, I had come across a blog post pointing to ADN Addin of the month being awarded to a similar Inventor addin which saves the active view as an image. I had developed IN-Screenshot atleast an year ago and have no link with the other addin.

# IN-Motion Released for Autodesk Inventor 2010

We have released IN-Motion for Autodesk Inventor 2010. IN-Motion is an affordable Motion and Dynamic Simulator for Autodesk Inventor. We had launched IN-Motion for 2009 version of Inventor earlier this year. Autodesk has certified IN-Motion to work with Inventor 2009 and 2010. We are also developing for 2011 version and would be available soon after Autodesk launches its product line for 2011 versions. For a detailed info on IN-Motion, check out IN-Motion 2009 blog entry. Download IN-Motion with 30 days free trial and once you are satisfied with it, you can buy a license for lifetime at just US\$ 200.

A screenshot of IN-Motion running on Autodesk Inventor 2010 is below.

Please keep checking this blog for more updates and tutorials on IN-Motion and also Dynamic Simulation using Autodesk Inventor. If you have any query, please email to the following

Happy IN-Motioning

# IN-Motion Launched for Autodesk Inventor 2009

Update: IN-Motion Released and Certified for Autodesk Inventor 2010.

Yes !! Finally we made it. After the extensive development of IN-Motion, we have launched it for Autodesk Inventor 2009. View Full Press Release. Download IN-Motion with 30 free trials

IN-Motion is an inexpensive Motion and Dynamic Simulation Addin for Autodesk Inventor. It has been certified by Autodesk to work with Autodesk Inventor 2009 version. We are in the process of developing IN-Motion for Autodesk Inventor 2010 and it should be released soonIN-Motion Released and Certified for Autodesk Inventor 2010 .

Check out the video below to get an overview of IN-Motion.

The Main Features of IN-Motion are:

IN-Motion is packed with all the above mentioned features and is available for download with 30 free trials. Once you are satisfied with our Addin, you can buy a lifetime license for just US\$ 200.

If you are an Autodesk Inventor user and wanted to learn Dynamic Simulation, we have free online video tutorials at http://www.ar-cad.com/in-motion/tutorials/index.html

Please keep checking this blog for more updates and tutorials on IN-Motion and also Dynamic Simulation using Autodesk Inventor. If you have any query, please email to the following

Happy IN-Motioning

# Happy New Year 2010 !!!!

What a great year 2009 was to me. I thoroughly enjoyed the roller-coaster ride.

• It started off with development of IN-Motion (Motion and Dynamic Simulation Addin for Autodesk Inventor)
• Shifted from Bangalore to Delhi. Joined Indian Institute of Technology Delhi, New Delhi as a Project Scientist.
• Got married to my college sweetheart in June.
• Appeared for MS(Research) interview at IITD and got through it :). M.S program started from July end.
• Finished off first sem of MS with CGPA 8.0/10
• Launched IN-Motion 2009 for Autodesk Inventor 2009
• Working on launch of IN-Motion 2010.

I hope 2010 will remain equally good if not more

Wish you all a Very Happy New Year !!!

Play Safe 😛

# ZedGraph C# Graph Data Export to CSV Using a Custom Context Menu

In continuation of my earlier post on ZedGraph example which plots a sinosoidal graph, I have extended it further to:

Export Graph plot data to CSV (coma separated values) file. Which can be opened by spreadsheets such as Microsoft Excel and Open Office calc.

For the custom context menu, the code has been derived from ZedGraph Wikipage. The following is the code of the Windows Form which has the ZedGraph control.

[sourcecode language=’c#’]
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using ZedGraph;
using System.IO;

namespace ZedGraphTest
{
public partial class Form1 : Form
{
private PointPairList m_pointPairList;
//CSV Writer
private StreamWriter m_CSVWriter;

public Form1()
{
InitializeComponent();
CreateGraph();
SetSize();

//csv
}

private void CreateGraph()
{
GraphPane myPane = zedGraphControl.GraphPane;

// Set the titles and axis labels
myPane.Title.Text = “ZedGraph Test”;
myPane.XAxis.Title.Text = “theta (angle)”;
myPane.YAxis.Title.Text = “Sin (theta)”;

// Make up some data points from the Sine function
m_pointPairList = new PointPairList();
{
_returnString = “”” + _string.Replace(“””, “”””) + “””;
}
return _returnString;
}

}
}

[/sourcecode]

# Zedgraph C# Graph Plot Example Application

Update : Check out ZedGraph C# Graph Data Export to CSV Using a Custom Context Menu , It has code to make a custom context menu item and also export the graph plot data as CSV.

Zedgraph is a very good opensource C# graph plotting library. Check out more details at my earlier post on Zedgraph. I have gone a step forward and made availabe source code and exe of a sample Zedgraph application which lets you have Line Plot, Bar Graph and Pie Chart.

Below are the Screenshots of the Window Application. Copy and paste 2 columns of data from your favorite spreadsheet(eg MS Excel, Open Office Calc etc). NewLine and Tab delimiters are identified and the data is sorted accordingly, and added to graph plots. The Zedgraph plot library is so easy to use, implement and extend that it just took an afternoon to come up with this Windows application, when I was trying to convince my cousin to use ZedGraph in his college project.

ZedGraph is also being used to plot graphs in IN-Motion, a Motion Simulation Addin for Autodesk Inventor which I am co-developing along with my mentor. We are using ZedGraph to plot Postition-Velocity-Acceleration data, and intend to use it further more in Force-Torque graphs etc. Thanks to ZedGraph team for such a wonderful effort

Figure 1: ZedGraph Sample Window Application

Figure 2: The plot data for Line Plot and BarGraph are copied from a spreadsheat (eg MS Excel) and pasted in the text area. The code then uses tab and newLine delimiters to arrange data for plotting.

Figure 3: Line Plot for the above data. Notice the Titles of the X and Y axes.

Figure 4: Bargraph for the above data.

Figure 5: Data for Pie Chart. Paste 2 columns from spreadsheet. You may also use normal textbox to get the data from the user.

Figure 6: Pie Chart for the above data.

# Free Autodesk Inventor Assembly Files

Update: IN-Motion, a Motion and Dynamic Simulation Addin for Autodesk Inventor has been launched by us.

Update: Video tutorials on usage of IN-Motion for Dynamic Simulation of Autodesk Inventor Assemblies.

Today, I stumbled upon a website which publishes textbooks, predominantly on CAD. While browsing through it, I figured out that they have a set of free Inventor assemblies, that can be downloaded. They can be found on this page on CADCIM. Scroll Down to section Inventor Files. A set of tutorials in pdf can also be found at the following URLs.

Update: Free Inventor Assembly files (used for Motion and Dynamic Simulation)

I shall try to update this blog post whenever I find more resources about free Autodesk Inventor parts or assemblies.

# Minimize forms along with Parent Application or Form in C#

How to minimize forms that belong to a particular application, when the parent application (In my case Autodesk Inventor) is minimized ? When you create software or addins, you would want the forms/dialogs to be minimized and not floating around when parent application is minimized.

For that we need to deal with hWnd of parent application. “hWnd” stands for Window Handle, which is the API call to the window(parent application). Since we come across this too often in Inventor customization to make addins, I have created a Class and a couple of methods for better clarity. Before I go into details, lets see what are the different types of Forms/Dialogs you would deal while developing Windows based software.

1)Modal Forms or Dialog Box

The modal forms are used when you want the user to enter some values and unless the form/dialog is closed, he/she cannot interact with other controls in the application. All the MessageBox’s are of modal types. The image on the left is also an example of Modal forms. Here, the user has to enter/select details of Graph plots in our addin IN-Motion.

2. Modeless Form

The modeless forms are used when user can enter values into the form and also can interact with other controls in application, even when the form is not minimized. The image on the left is the Simulation playback deck in IN-Motion.

Coming back to our problem of minimizing forms with parent application, below is the code. If the user minimizes Inventor application(parent form), its child forms are also minimized.
[sourcecode language=’c#’]
//
//Declare and set..here m_inventorApplication is the application
//MainFrameHWND returns its handle.
//WindowsWrapperForForm is a Class, defined at the bottom
WindowsWrapperForForm m_windowsWrapperForForm = new
WindowsWrapperForForm((IntPtr)m_inventorApplication.MainFrameHWND);

//Declare and set a form .. ModalCmdDlg is our modal form
ModalCmdDlg m_modalCmdDlg = new ModalCmdDlg();

//Declare and set a form .. ModelessCmdDlg is our modeless form
ModelessCmdDlg m_modelessCmdDlg = new ModelessCmdDlg();

//Show Modal form
ShowModalForm(m_modalCmdDlg);

//Show Modeless form
ShowModelessForm(m_modelessCmdDlg);

//Methods
private void ShowModalForm(Form _modalCmdDlg)
{
_modalCmdDlg.Activate();
//ShowDialog is used..for Modal forms
_modalCmdDlg.ShowDialog(m_windowsWrapperForForm);
}

private void ShowModelessForm(Form _modelessCmdDlg)
{
_modelessCmdDlg.Activate();
//Show is used..for Modeless forms
_modelessCmdDlg.Show(m_windowsWrapperForForm);
}

//Below is the code for Class WindowsWrapperForForm
//****************Class***************

class WindowsWrapperForForm : System.Windows.Forms.IWin32Window

{
private IntPtr m_hwnd;
public WindowsWrapperForForm(IntPtr handle)
{
m_hwnd = handle;
}
#region IWin32Window Members
public IntPtr Handle
{
get { return m_hwnd; }
}
#endregion
}
//****************EndClass*******************

[/sourcecode]

# Opensource C# Graph Plot Library – ZedGraph

Update: Check out Zedgraph C# Graph Plot Example Application , I have an example ZedGraph Application (with sourcecode) to draw Line Plot, Bar Graph and Pie Chart.

Update 2: Check out ZedGraph C# Graph Data Export to CSV Using a Custom Context Menu , It has code to make a custom context menu item and also export the graph plot data as CSV.

I was searching for an opensource(hence free) Graph plotting library in C# (or VB.NET), so that it could be used in our IN-Motion addin for Autodesk Inventor. After some googling, I found 2 suitable open source libraries namely ZedGraph and NPlot. When both websites(read wiki) were compared, I found ZedGraph recently updated and also had great documentation to take off immediately. I readily downloaded the latest version of ZedGraph dll from its SourceForge project and followed the instructions on ZedGraph wiki.

Within no time, I was ready with ZedGraphTest example, whose screenshot is above. It is so simple that, without even exploring, I could accomplish basic graph plotting. Some of the plus points I see in ZedGraph are:

• Not much tweaking of source-code is required for basic tasks.
• All the plot elements (line, curve, panel, axes, plot-markers etc) can be set different colors. Even gradients can be set to have crazy as well as good looking Graphs
• Different types of graphs (line,bar,pie etc) are possible with ease.
• Using left click on the plot panel, the graph can be zoomed
• Middle button can be used to pan the plot
• Upon right click over the plot, a context menu appears which, out of the box has a lot of useful features such as saving the image, toggle the on-hover highligthing etc
The code for my ZedGraphTest is below. I have changed only CreateGraph() method, and the remaining code is same as in the example.
[sourcecode language=’c#’]
private void CreateGraph(ZedGraphControl zgc)
{
GraphPane myPane = zgc.GraphPane;

// Set the titles and axis labels
myPane.Title.Text = “ZedGraph Test”;
myPane.XAxis.Title.Text = “theta (angle)”;
myPane.YAxis.Title.Text = “Sin (theta)”;

// Make up some data points from the Sine function
PointPairList _list1 = new PointPairList();
for (double x = 0; x <= 360; x += 10) { double y = Math.Sin(x * Math.PI / 180.0); _list1.Add(x, y); } // Generate a blue curve with Plus symbols, LineItem _myCurve1 = myPane.AddCurve("Sin (theta)", _list1, Color.Blue,SymbolType.Plus); // Fill the pane background with a color gradient myPane.Fill = new Fill(Color.White, Color.FromArgb(220, 220, 255), 45F); //Make the MajorGrids of Axes visible myPane.XAxis.MajorGrid.IsVisible = true; myPane.YAxis.MajorGrid.IsVisible = true; // Calculate the Axis Scale Ranges zgc.AxisChange(); } [/sourcecode] So far, this library has been a boon to me as I dont have to reinvent the wheel again. Thanks a ton to ZedGraph guys