Inventor 2021 Axis triad and View

[TDno]

Good day everyone,

I have been using Inventor to model my 3D parts and today, while doing an assembly, I noticed something that, in my view, is weird. It seems that Inventor triad axis isn't what i supposed it was. For example, i was expecting that the Z axis was related to the Top/Bottom view and not the Front/Back as shown in the image:

Can someone explain me the logic behind this coordinate system?

I tried to change the view using the ViewCube Orientation, like so:

Unfortunately, it seems that this setting didn't change nothing in my view. How could i change the default view so that my Z axis corresponds to Top/Bottom, X to Front/Back and Y to Left/Right?

Thanks for any help

[JDMather · Accepted solution]

Set the view to desired orientation.

Right click on the view cube and set Top or Front as desired.

[TDno]

Ok, so, what you mentioned changed my view (triad is now alright) and I set it as I intended. Now the problem seems that Inventor exports the model using the old system (Z as Front View)?

[TDno]

Ok, my problem seems to be related to the following issue:

Import & Export: Y-Up and Z-Up options - Autodesk Community

Is there a process to export with Z-up? And how can I make the Inertial Properties reflect the change on view (because they don't change)?

[johnsonshiue]

Hi! There are multiple related workflows regarding this particular topic. I think you need to do the followings.

1) For existing components, make sure you redefine the ViewCube Orientation (Z-top) as JD indicated.

2) Also, change the ViewCueb orientation in the Standard iam and ipt templates.

3) In the standard ipt template files, make sure all origin planes are visible. So that ViewCube will not reorient itself when you create the first sketch.

Many thanks!

[TDno]

Editing ViewCube doesn't seem to resolve the problem with the export (mainly .obj and .stl). There isn't a workaround?

Thanks

[johnsonshiue]

Hi! To help me understand the issue, I would like to see a few things. Please share the ipt file, the standard ipt template file.

Many thanks!

[TDno]

I will post a simple part, just to show my point. The part was done in Inventor, exported as obj and opened in blender. As you can see, in inventor, part is done on XZ plane but part exported defaults to previous view (change on ViewCube doesn't seem to influence export), showing it as being sketched on XY plane.

Thanks for the help

 Part in Inventor, sketched on XZ plane          Part exported, still using old coordinate system

PS: It seems i have replied to myself and cannot edit it to change my reply to you, @johnsonshiue 

[johnsonshiue]

Hi! Many thanks for sharing the files! I believe the issue here is about both the ViewCube and the Sketch orientation. Please note that the export has nothing to do with ViewCube. The ViewCube is just like a camera. It cannot change the 3D object. It only change the view point and direction.

The ViewCube in the both files were not set up correctly. If I understood Z-up orientation correctly, XZ plane should be the front plane and Z points to the top. I have redefined it in the files accordingly.

Regarding the cylinder, it was created on XZ plane. I assume it should be in the XY plane. I also redefined it to XY plane (right-click on the sketch -> Redefine -> select XY plane). Please take a look at attached parts.

Many thanks!

[TDno]

Thanks for your reply. The Z up coordinate system I'm used to (the one I work with and the one I learned), Z+ corresponds to Top, X+ to forward and Y+ to left. A similar coordinate system is used in aeronautical systems (multicopters, for example), with the difference that Z+ is down (points towards the inertial frame - Earth) and the inertial coordinate system is represented with the Top being Z+. I attach an example image to explain:

So, following this image, and imagining the coordinate system with Z pointing up, from my understanding, in Inventor, plane YZ should correspond to front view (X-) and top view corresponds to XY (Z-), correct?

Besides, I have tried out  your corrected part, according to the coordinate system you used, and still Inventor exports it incorrectly (what you see in Inventor is not what you get in the exported object). It seems Inventor exports always with Y-up coordinate system. How can I correct this? Or isn't there any way besides doing assemblies with my parts to do the exports as I need them (which is somewhat a tedious process)?

Corrected part in InventorCorrected part in Blender

[johnsonshiue]

Hi! I am sorry I am confused now. The export files from Inventor do not carry ViewCube data. Only the geometry and its orientation relative to XYZ are exported.

What format did you export to Blender? obj/stl or STEP? Please share the exported file also.

Many thanks!

[TDno]

In this case, I have simply opened your file and exported as .obj. I have attached the exported files. The exported files when used in other programs (as in the case of Blender and ROS) doesn't have the correct orientation when compared to the orientation given by Inventor.

To explain why the use of Blender, I have been exporting the files from Inventor as .obj and used blender to export them as .dae (easier method I have found, if you know any other please let me know). 

[johnsonshiue]

Hi! I think the confusion is what drives the ViewCube orientation. Each CAD system dictates its orientation. However, the geometry and its position relative to the coordinate system should remain unchanged.

Inventor cannot tell how Blender to orient its model. You will need to change it in Blender, vice versa.

Many thanks!

[JDMather]

Why not simply model relative to desired XYZ and completely ignore the words as written on the View Cube?

Once modeling relative to XYZ is mastered - then I can return in discussion of words.

[TDno]

"Each CAD system dictates its orientation" - so, the conclusion is that Inventor uses Y-Up orientation (from what I read in other threads, such as Solved: Swapping Y and Z axes in an assembly - Autodesk Community - Inventor) and that cannot be changed, Am I correct to assume that is this that is being said? Sorry for this question, but got a bit confused.

[TDno]

Thanks for all your support, all the problems that I was having was from the Blender import side. Please ignore my last reply, I cannot edit it any longer. Sorry for all the trouble! 

[johnsonshiue]

Hi! Indeed, by default Inventor set up ViewCube with Y-up (as opposed to Z-up). But, this setting can be changed. Also, it has nothing to do with how the geometry is exported. Like I mentioned repeatedly, the geometry has to be precise in size and its location relative to XYZ.

Think of the ViewCube as a camera. A viewing device cannot change a 3D object. It only changes the view point. Blender has its own setup. You will need to figure out how to orient the model desirably there. If you can show me a case that the exported geometry and its location relative to XYZ from Inventor is wrong, please let me know. That will be a bug.

Many thanks!