topic Re: Dimensions are not correct in Inventor Forum

Dimensions are not correct

hwu — Thu, 06 Jul 2023 11:30:22 GMT

The holes' location dimensions should exactly be 0.6875 as shown in the front view. But on the top view, the dimensions on the curve is not exactly correct. What causes this and how to fix it? I am sure the model is right.

My Inventor is 2023

Best regards,

HWU

Re: Dimensions are not correct

CCarreiras — Thu, 06 Jul 2023 11:53:04 GMT

HI!

Try to create a center mark for each arc. Check if both have the same center.

can you share the file?

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 13:59:10 GMT

Thank you. when I add center marks, the whole circles are chosen. The dimensions are still not perfect.

Please have a look at the attached files.

Best regards,

Re: Dimensions are not correct

ReinierP5648 — Thu, 06 Jul 2023 14:30:50 GMT

The Center mark of the big hole in topview is not correct placed. that is your issue

Re: Dimensions are not correct

CCarreiras — Thu, 06 Jul 2023 14:30:51 GMT

HI!

What do you mean by "dimensions not perfect"

Seams right to me:

Re: Dimensions are not correct

LT.Rusty — Thu, 06 Jul 2023 14:36:58 GMT

(edited- I missed something.)

Re: Dimensions are not correct

Ivan_Sinicyn — Thu, 06 Jul 2023 14:36:37 GMT

This is more likely due to the geometry of the part. The top view projects a curve, not a circle. If you turn the part upside down, the dimensions are correct.

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 15:03:00 GMT

Thank you. How did you make the dimensions perfect? Can you make the red-marked dimensions perfect as well? Can you please send me the drawing that you corrected?

Best regards,

HWU

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 15:05:20 GMT

Thank you. You are right, but I like to show the dimensions in top view.

Best regards,

HWU

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 15:07:57 GMT

Thank you.

How did you find it was wrong? I cannot figure out what was wrong with the big hole center mark.

Best regards,

HWU

Re: Dimensions are not correct

Ivan_Sinicyn — Thu, 06 Jul 2023 15:18:59 GMT

I flipped the view. Clicked to set the centerlines automatically and flipped the view back.

Re: Dimensions are not correct

Anonymous — Thu, 06 Jul 2023 15:29:12 GMT

Have you considered using Model Dimensions in your drawing view?

You've already got the parameters in the model, use model dims on the drawing and you're all set.

Plus, you can edit these dims in the drawing, no need to open the model and the drawing to refresh it.

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 16:27:01 GMT

Thank you. Actually, I would like to know why there is the issue.

I also use "Include" the point feature to created center marked, then dimension them. This works as well.

Thanks,

HWU

Re: Dimensions are not correct

JDMather — Thu, 06 Jul 2023 16:39:03 GMT

@hwu wrote:

Actually, I would like to know why there is the issue.

These three curves are NOT circles in the 3D model.

They may show as circles projected into 2D, but actually splines with some behind the scenes conversion prone to rounding error. Normally we do not show dimensions out to 6 decimal places as that cannot be measured or manufactured.

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 16:39:57 GMT

Thank you. I was wondering why the dimensions were not perfect?

Best regards.

HWU

Re: Dimensions are not correct

JDMather — Thu, 06 Jul 2023 16:44:12 GMT

@hwu

But of course, on the other side of the part where the cylinders cut though perpendicular planar face, they are true circles. That is why the bottom view worked.

Re: Dimensions are not correct

hwu — Thu, 06 Jul 2023 16:49:48 GMT

Thank you,

I cannot get what you show here.

After flipped back, there is not center marks, but the blue points.

Best regards,

HWU

Re: Dimensions are not correct

LT.Rusty — Thu, 06 Jul 2023 19:49:41 GMT

Another way you can get it to work right (without flipping the part) is to use the centerline tool, rather than the center mark.

Using the centerline tool, draw a CL from the left side to the first hole, then the second, the third, and finally stop at the right edge of the part. For me, this put everything in the correct location.

Re: Dimensions are not correct

Anonymous — Thu, 06 Jul 2023 22:48:24 GMT

@JDMather beat me to it, he's exactly correct in his explanation.

Re: Dimensions are not correct

hwu — Fri, 07 Jul 2023 11:26:58 GMT

Thank you,

I cannot make it by following your way. The dimensions are still not perfect in the top view.

Best regards,

HWU