I need your help to improve this matrix transformations how-to

Discussion created by Peter Brinkhuis on Aug 2, 2019
Latest reply on Aug 3, 2019 by Peter Brinkhuis

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Hello my fellow SOLIDWORKS API programmers,

Last week I was struggling a lot with matrix transformations, as you could have read in this topic. I found the API help to be unclear and incomplete. On top of that, API support couldn't really explain the concepts to me and they gave me one answer which I still think is wrong.

So I wrote a big blog post to share everything that I know about matrix transformations. I start with the very basics, what is a matrix and what is a transformation. I then show how they are used within SOLIDWORKS as IMathTransform and I end it all with a list of useful macros and forum topics.

Here it is:

https://cadbooster.com/complete-overview-of-matrix-transformations-in-the-solidworks-api/

I would love your input to make this post even better. Besides fixing errors, the main things I still want to improve:

Add API commands with the space of their returns values!!
More API examples
More links to useful articles and macros

What information or which link would you like to include in this article? What info were you missing while you were messing with transformations? Every improvement is appreciated.

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Rob Edwards Aug 3, 2019 12:43 PM

Hi Peter

Brilliant! - Nice work thankyou

I shared a similar experience delving into transforms earlier this year. I spent a couple of days with my head completely battered.. so your blog would have been nice to have then.. and as my old brain doesn't retain information so well these days I'm sure I'll check it out again.

I have an example I can share that uses

CreateTransformRotateAxis Method (IMathUtility)

ComposeTransform Method (IMathUtility)

Cross Method (IMathVector)

Dot Method (IMathVector)

[edit]

It also includes a function for ACos which is missing in VBA.

Private Function Acos(x As Double) As Double
   If Abs(x) <> 1 Then
      Acos = Atn(-x / Sqr((-x * x) + 1)) + 2 * Atn(1)
   Else
      Acos = IIf(x > 0, 0#, 2 * Atn(1))
   End If
End Function

Just found it! missing in VBA but provided by SW

[edit]

The macro doesn't do much.

It takes a face - looks for an entity named "MeMeMe" - and obtains the underlying surface.

It then creates a transform to rotate to the front plane.

It then just grabs the vertices and adds a 3d sketch of the vertices before and after transformation.

In the part attached I manually added a sketch point and axis that show the root point of the surface.

Maybe it's helpful to someone, unfortunately I didn't comment it very well.

Thanks again

Have a sweet weekend!

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Peter Brinkhuis @ Rob Edwards on Aug 2, 2019 3:01 PM

Thanks Rob I'll check out your macro tomorrow to see which lessons I can extract from it.

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Josh Brady Aug 2, 2019 3:57 PM

This is definitely great work, Peter! What the heck a transform even is can be pretty daunting, much less how to use one. I was pretty fortunate when it came to transforms in SW API because I'd gotten to "play" with them in a robotics course. They're one of the main tools used to solve the kinematics of any robot. Of course, I learned them on paper and did a bunch of those manipulations by hand calc. Much easier when SW does the heavy lifting!

Interestingly enough, even though I worked with robots for years afterward, I never touched transforms again until I encountered them in the API. The robot software I used handled all that behind the scenes.

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Peter Brinkhuis @ Josh Brady on Aug 3, 2019 4:18 PM

Thanks Josh! Yes they can be daunting (certainly because you have to jump through hoops to see what's inside SW objects). That is the exact reason I started with the very basics. If you know that, then you might be able to debug your process and the answers in between transformations as well.

I have hardly even needed matrices after university, let alone transformations. I missed out (although I didn't think of it that way at the time) on a course on robotics and transformations at the time.

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Artem Taturevych Aug 2, 2019 10:24 PM

Excellent, article, Peter! I really like how your deep look at matrices and explain mathematical component of that as at the end of the day all the functions within the IMathUtils are based on the math and can be calculated manually.

I also have few examples for matrices under Using transformations in SOLIDWORKS API section. I would also mention the transformation matrix for the temp bodies as it is usually used in macro features and previews. I have an example which rotates the body around axis without adding any features into feature tree: Create body rotation animation using SOLIDWORKS API, similar one for components: Run rotation animation for the component using SOLIDWORKS API

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Peter Brinkhuis @ Artem Taturevych on Aug 3, 2019 4:25 PM

Thank you Artem. Great to see that you also wrote a post to get started with transforms. I kinda like the way the 4x4 matrix looks in your representation with only ones in the first column.

I'll add a link to your post in my post. That way you can keep adding examples and my readers can find out about them.

Temporary bodies is a good one to add, yes. I never knew they existed until I made that list of all methods that return a transform.

Actions

6 Replies

Rob Edwards Aug 3, 2019 12:43 PM
Hi Peter
Brilliant! - Nice work thankyou

I shared a similar experience delving into transforms earlier this year. I spent a couple of days with my head completely battered.. so your blog would have been nice to have then.. and as my old brain doesn't retain information so well these days I'm sure I'll check it out again.

I have an example I can share that uses
CreateTransformRotateAxis Method (IMathUtility)
ComposeTransform Method (IMathUtility)
Cross Method (IMathVector)
Dot Method (IMathVector)

[edit]
It also includes a function for ACos which is missing in VBA.
Private Function Acos(x As Double) As Double
   If Abs(x) <> 1 Then
      Acos = Atn(-x / Sqr((-x * x) + 1)) + 2 * Atn(1)
   Else
      Acos = IIf(x > 0, 0#, 2 * Atn(1))
   End If
End Function
Just found it! missing in VBA but provided by SW
[edit]

The macro doesn't do much.

It takes a face - looks for an entity named "MeMeMe" - and obtains the underlying surface.
It then creates a transform to rotate to the front plane.

It then just grabs the vertices and adds a 3d sketch of the vertices before and after transformation.

In the part attached I manually added a sketch point and axis that show the root point of the surface.

Maybe it's helpful to someone, unfortunately I didn't comment it very well.

Thanks again

Have a sweet weekend!
Attachments
- Transform.swp.zip15.6 KB
- TransformTest.SLDPRT.zip67.2 KB
- Transform1.bas.zip1.3 KB
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- Peter Brinkhuis @ Rob Edwards on Aug 2, 2019 3:01 PM
  Thanks Rob I'll check out your macro tomorrow to see which lessons I can extract from it.
  Like • Show 1 Like1
  Actions
Josh Brady Aug 2, 2019 3:57 PM
This is definitely great work, Peter! What the heck a transform even is can be pretty daunting, much less how to use one. I was pretty fortunate when it came to transforms in SW API because I'd gotten to "play" with them in a robotics course. They're one of the main tools used to solve the kinematics of any robot. Of course, I learned them on paper and did a bunch of those manipulations by hand calc. Much easier when SW does the heavy lifting!

Interestingly enough, even though I worked with robots for years afterward, I never touched transforms again until I encountered them in the API. The robot software I used handled all that behind the scenes.
Like • Show 1 Like1
Actions
- Peter Brinkhuis @ Josh Brady on Aug 3, 2019 4:18 PM
  Thanks Josh! Yes they can be daunting (certainly because you have to jump through hoops to see what's inside SW objects). That is the exact reason I started with the very basics. If you know that, then you might be able to debug your process and the answers in between transformations as well.
  
  I have hardly even needed matrices after university, let alone transformations. I missed out (although I didn't think of it that way at the time) on a course on robotics and transformations at the time.
  Like • Show 0 Likes0
  Actions
Artem Taturevych Aug 2, 2019 10:24 PM
Excellent, article, Peter! I really like how your deep look at matrices and explain mathematical component of that as at the end of the day all the functions within the IMathUtils are based on the math and can be calculated manually.

I also have few examples for matrices under Using transformations in SOLIDWORKS API section. I would also mention the transformation matrix for the temp bodies as it is usually used in macro features and previews. I have an example which rotates the body around axis without adding any features into feature tree: Create body rotation animation using SOLIDWORKS API, similar one for components: Run rotation animation for the component using SOLIDWORKS API
Like • Show 1 Like1
Actions
- Peter Brinkhuis @ Artem Taturevych on Aug 3, 2019 4:25 PM
  Thank you Artem. Great to see that you also wrote a post to get started with transforms. I kinda like the way the 4x4 matrix looks in your representation with only ones in the first column.
  
  I'll add a link to your post in my post. That way you can keep adding examples and my readers can find out about them.
  
  Temporary bodies is a good one to add, yes. I never knew they existed until I made that list of all methods that return a transform.
  Like • Show 0 Likes0
  Actions

I need your help to improve this matrix transformations how-to

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