topic Re: True dimensions wrong in Inventor Forum

True dimensions wrong

bhuhn — Wed, 13 Apr 2022 16:05:49 GMT

I'm trying to annotate the dimensions of a conical shape along specific 3dSketch geometry. Dimensioning the lines only gives me the dimensions perpendicular to the sketch plane. I have also tried changing the "General Dimension Type" to "True" instead of "Projected" - but this results in a dimension that is nowhere close to the true length of the line and some real wonky-looking dimension lines.

I have also tried adding a leader to the line and seeing if there is a field for the length of the line, but this does not seem to be an option. Ideally, the length would be called out on a leader for what I'm going for here - but I can't even get the true dimension either way.

I would also need to be able to get the true length from one point to another along the line in some instances - so automating from a field for the line's total length would not help in that case.

...Neither of the dimensions above are right - as shown from the model image below:

Any suggestions?

Re: True dimensions wrong

johnsonshiue — Wed, 13 Apr 2022 21:35:31 GMT

Hi! The isometric dimension is based on 3D geometry. But, the dimension style is limited. You may not be able to orient the dimension desirably. To properly annotate in 3D space, you need to create the dimension in 3D. Open the part and go to Annotate -> Dimension. After that, retrieve the dimension in the drawing.

Many thanks!

Re: True dimensions wrong

bhuhn — Thu, 14 Apr 2022 14:36:43 GMT

That sounds like it could work - but the dimension option is greyed out on all levels of the frame assembly file. Maybe I should have mentioned that this is a frame assembly. I just need the on-center dimensions of the frame, which is why we're looking at the reference skeleton.

Re: True dimensions wrong

johnsonshiue — Fri, 15 Apr 2022 18:05:04 GMT

Hi! I am sorry I am missing something here. 3D Annotate workflows should be allowed for any components (parts and assemblies) including frame members. I would like to see an example that exhibits otherwise behaviors

Many thanks!

Re: True dimensions wrong

munyua44 — Sun, 17 Apr 2022 13:49:54 GMT

try converting into three-dimensional to see if it is possible to change the dimensions.

Re: True dimensions wrong

bhuhn — Mon, 18 Apr 2022 13:59:35 GMT

Everything but the viewplane is 3d already. Can you elaborate on what you mean when you say to convert it to 3d? Do you mean the dimension lines?

Re: True dimensions wrong

CGBenner — Mon, 18 Apr 2022 15:46:46 GMT

@bhuhn

If this is a frame assembly, try to right mouse click on the part file containing your sketch, on the sketch itself, and use Include to project the sketch into the drawing view. Then you can dimension directly to that, and you should get the same dimensions you used when creating the sketch. This is a crude image, put together quickly...

Re: True dimensions wrong

bhuhn — Mon, 18 Apr 2022 18:57:07 GMT

So that's exactly what I did in this image on the first post...

...The first issue being the wonky-looking dimension lines and squished text (probably a result of this being in plan view looking at a slightly conical ceiling cloud as opposed to the nice isometric you have shown), the second being that the dimension is simply wrong... I'm thinking I might need to make this diagram in Sketchup if I want an easy way to dimension these lines.

Re: True dimensions wrong

SBix26 — Mon, 18 Apr 2022 20:16:47 GMT

The "wonky-looking dimension lines and squished text" are simply because the view is not orthogonal to the origin planes, and Inventor always places dimensions in that situation as 3D dimensions oriented to the origin planes. In an ordinary isometric view, that is typically pretty helpful.

In order to figure out how to get what you want, we'll need an example drawing & part. I think this can be done, but I'm not certain, and I'm not going to spend a bunch of time trying to create something which may or may not mimic your situation. What version of Inventor are you using?

Sam B

Inventor Pro 2023 | Windows 10 Home 21H2

Re: True dimensions wrong

johnsonshiue — Mon, 18 Apr 2022 21:15:08 GMT

Hi! I think you are dimensioning an Isoview with dimension type set to True. Such dimension is taken from the 3D geometry directly. If it does not make sense, please share the files here. I would like to understand the behavior better.

Many thanks!

Re: True dimensions wrong

bhuhn — Mon, 18 Apr 2022 21:30:27 GMT

Here is the part file. Pretty much all my tools are grayed out when I go into the 3d sketch. Can't alter the sketch. Can't annotate. Let me know if it's different for you. Thanks!

Re: True dimensions wrong

johnsonshiue — Mon, 18 Apr 2022 22:00:13 GMT

Hi! I see the part now. It has a 3D Sketch. I thought there was body geometry. Indeed, 3DA/MBD does not support 3D Sketch geometry as it does for 2D Sketches. Are these 3D lines in the same group on a 2D plane? Or they are all in 3D?

Many thanks!