Community
Inventor Forum
Welcome to Autodesk’s Inventor Forums. Share your knowledge, ask questions, and explore popular Inventor topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

3d sketch equation curve

4 REPLIES 4
SOLVED
Reply
Message 1 of 5
JDMather
5878 Views, 4 Replies

3d sketch equation curve

I'm just starting out with learning equation curves in Inventor.

 

How can I get this curve

r(t)= ti + 4cos tj +9sin tk; where t is greater than or equal to 0

 

I would also like to figure out how to get this VBA as an equation curve

(see attached file)


-----------------------------------------------------------------------------------------
Autodesk Inventor 2019 Certified Professional
Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional


The CADWhisperer YouTube Channel


EESignature

4 REPLIES 4
Message 2 of 5
glenn-chun
in reply to: JDMather


@Anonymous wrote:

How can I get this curve

r(t)= ti + 4cos tj +9sin tk; where t is greater than or equal to 0


 

Hi JD,

 

I will use five turns for the elliptical helix for illustration purpose.  Enter the following Cartesian coordinates in the Equation Curve command:

 

x(t) = t

y(t) = 4 * cos(t)

z(t) = 9 * sin(t)

 

and you will see this elliptical helix:

 

eq_crv1.png

 

Or a much thinner curve:

 

eq_crv2.png

 

Note that the parameter t is unitless, but the sine and cosine functions can take angles in either radians or degrees.  When rad or deg is not specified inside sin() or cos(), the angle unit from the Document Settings is used.

 

angle_unit.png

The first and second curves above use radians and degrees, respectively.  I believe that the first curve is what you want to create.

 

You can check the Show units option to see all the hidden units.

 

eq_crv3.png

 

eq_crv4.png

 

The following example shows a bad practice in my opinion. Degrees are used in sin() and cos(), and the parameter t is converted from degrees to radians.  It sort of works but could be confusing and misleading.

 

eq_crv5.png

 

I think it's better to specify the angle unit explicitly in sin() and cos().  Simply add 1rad* or 1deg* inside the function.  That will override the angle unit specified in the Document Settings

 

eq_crv6.png

 

Also, beware of equations that imply the number of turns.  Two examples are shown below.

 

eq_crv7.png

 

eq_crv8.png

 

Hope this helps,

 

Glenn

Autodesk ShapeManager Development



Glenn Chun
Sr. Principal Engineer
Message 3 of 5
JDMather
in reply to: glenn-chun

Thanks, this is great.

 

Pulled out my college Calculus book from 30 years ago and started recalling all these curves we plotted out by hand.

 

Do you guys realize what you have?

I think a lot of facutly still think of Inventor as an electronic drafting board - something beneath their status.

This is a full fledged engineering tool not just a specialized field (MCAD) version of AutoCAD.

Far more interesting than using a graphing calculator and certainly more fun that plotting by hand.

 

I think you guys should find the most popular physics textbook in use and set up all the problems in Dynamic Simulation (or whatever simulation tool needed).

Find the most popular calculus textbook in use and set up all the relevant problems in Inventor.

Make this stuff more interesting.  Make this stuff real for the 21 century.

Somebody is going to do it (a lot of related iPhone apps already appearing).

You could create a comprehensive engineering education tool that would revolutionize the way this stuff is taught.

My daughter went to all electronic books this semester.

You guys could own this (engineering education for the 21 century).


-----------------------------------------------------------------------------------------
Autodesk Inventor 2019 Certified Professional
Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional


The CADWhisperer YouTube Channel


EESignature

Message 4 of 5
SMPConsulting
in reply to: JDMather

Came accoss your post @JDMather  after researching for a solution to an issue with lofted surface geomtry and thought the post was worthy of bumping as it resonated with me. Your points are still incredibly relevant today in 2019.

 

A lot of industry still think CAD is an electronic drafting board and are missing out on the incredibly diverse applicatinos and benefits to providing practical mathematical and physics driven design and engineering solutions.

 

  

 

Anthony Paul
www.smpconsulting.com.au
An Inventor user since IV6 2002, and a 3D AutoCad user since R9 1989

i7 7770 @ 3.6GHz – 4.2, GB H110M M.2 Mainboard, 2 x 8 GB DDR4 RAM
250 GB SSD 960 Evo Series SSD, 700 W 80+ ATX Power Supply, Win 10 Home 64 Bit
Message 5 of 5
JDMather
in reply to: SMPConsulting

I pushed this as hard as I could with Autodesk for many years.

The only person who heard my voice has now retired from Autodesk.

I have given up with Autodesk and setting up communication channels to continue this discussion with SolidWorks.


-----------------------------------------------------------------------------------------
Autodesk Inventor 2019 Certified Professional
Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional


The CADWhisperer YouTube Channel


EESignature

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Autodesk Design & Make Report