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## Autodesk Inventor

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Posts: 55
Registered: ‎12-06-2008

# Gravity – Dynamic Simulation

295 Views, 5 Replies
11-12-2012 12:09 PM

Gravity – Dynamic Simulation

I’ve been working with gravity experiments and have been successful achieving realistic results for the most part. Thanks to help I received here. There are some basic questions that I need to get a handle on and I would appreciate any input.

1. If I lower the gravity number from 300 down to 150 for example, is this the same as if reducing the weight by half for the objects that are free to move in the simulation?
2. If it is not too time consuming I would appreciate information on how to input a desired weight for a moveable object.

Thanks,

Bill

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Posts: 21,911
Registered: ‎04-20-2006

# Re: Gravity – Dynamic Simulation

11-12-2012 01:06 PM in reply to: billjenkins

Set the materials for the part(s) or override the iProperties physical properties.  (you don't state what version of Inventor you are using - material properties slightly different for 2013)

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Valued Contributor
Posts: 90
Registered: ‎06-09-2008

# Re: Gravity – Dynamic Simulation

11-12-2012 01:14 PM in reply to: billjenkins

billjenkins wrote:
1. If I lower the gravity number from 300 down to 150 for example, is this the same as if reducing the weight by half for the objects that are free to move in the simulation?

I'm guessing you mean mass, not weight.  Reducing gravity by 50% is not equivalent to reducing the mass of the object by 50%

-Autodesk Inventor Professional 2012
Valued Contributor
Posts: 55
Registered: ‎12-06-2008

# Re: Gravity – Dynamic Simulation

11-12-2012 03:57 PM in reply to: billjenkins

Thanks, I’ll see if I can follow your directions. Sorry, I forgot to mention I use Inventor Pro 2009. From the other response I assume that I cannot make a part a specific weight but if you have a method for doing so please let me know.

Before I check “accept as solution” I want to give you or anyone else a chance to offer any other tips that may be helpful. Making a part a specific weight is what I need to do if possible.

Thanks for the responses and sorry if I’m asking a question that is much more complicated than can be answered in a few short sentences.

Bill

Inventor Pro 2009

Valued Contributor
Posts: 90
Registered: ‎06-09-2008

# Re: Gravity – Dynamic Simulation

11-13-2012 04:13 AM in reply to: billjenkins

Go to the "Manage" tab > Styles and Standards > Styles Editor

In the left hand column, expand the material category, and find the material for your object.  Note the value in the "Density" field for this material.  Now click the "New" button, which will create a new material with the same properties as the currently selected material.

Find the new material in the left hand column, and double click (or right click > Activate) to apply this new material to your object.

Reduce the "Density" value of this material to half of its original value, thus reducing the mass of your object by half.

Also, just to make sure you're using the right terminology, reducing gravity by 50% will reduce the weight of an object by half, without changing its mass.  Weight is a measurement of the force of gravity on an object.

-Autodesk Inventor Professional 2012
Valued Contributor
Posts: 55
Registered: ‎12-06-2008

# Re: Gravity – Dynamic Simulation

11-13-2012 04:50 AM in reply to: billjenkins

Thanks, I experimented with the Physical Tab Located in iProperties and I now see that your method will also allow me to select a material. This is what I needed. I now keep gravity set at 386.220. Until now I’ve had to lower the gravity number in Dynamic Simulation. The simulations seem much more reliable and realistic now.

I would like to set the requested accuracy option to Very High. After making the change to Very High it looks as if the input was accepted but when I check the properties at a later time the LOW setting is what is displayed in the window.

This may be too deep to get into but I wish I could determine the weight of a part that I’ve applied a specific material property to. It’s not that important now that you guys have explained the material set up but I would like to leave this thread open for a little longer just in case someone wants to respond.

Thank You,

Bill  -  Inventor 2009