Announcements
Attention for Customers without Multi-Factor Authentication or Single Sign-On - OTP Verification rolls out April 2025. Read all about it here.

Fully constrained sketch won't change its color

PremTM
Advocate

Fully constrained sketch won't change its color

PremTM
Advocate
Advocate

Hi!

 

I am new to Inventor, basically it's my first project using this software. I've made a few parts already but now I have run into a strange thing. I have attatched a screenshot of the sketch (actually first part of it) where it occured. As you can see in the bottom right corner it is fully constrained yet those 2 green lines have not changed their color to blue as they should. The last operation I performed was the highlighted 'tangent constrain' applied to the small arc and construction circle to fit the arc curve to the circle. I am wondering why does this happen?

 

Apart from that extrusion works perfectly fine, I get the solid without any alerts. The color stays after I reopen the file, extrude this sketch, etc. Since it's fully constrained I'm unable to move any part and it's perfectly fine.

 

Edit:

When instead of tangent constrain I just set a dimension of the small arc it stays the same. Both lines stay green.

 

Best regards,

Tom

0 Likes
Reply
4,494 Views
16 Replies
Replies (16)

JDMather
Consultant
Consultant

Attach your *.ipt file here.


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


0 Likes

PremTM
Advocate
Advocate

Thanks for your response, it's been attatched below. I've changed it slightly (offset added and angle changed). Nothing that would have influence on this matter.

0 Likes

Anonymous
Not applicable

It looks like you need an additional contraint.

 

Try this:

 

Draw a vertical construction line constrained to the origin point.

 

Constrain the midpoint of the 30 rad arc to the new construction line.

 

or

 

Create an angular dimension to one of the green lines  and the new construction line.

 

 

0 Likes

PremTM
Advocate
Advocate

Thanks for your reply bmckaskle!

 

I am not sure how could I constrain a midpoint of any of those lines to the vertical one. Which operation could it be? And there already is a vertical construction line going through the axis. The outer 30 deg lines are constrained to it using the angular dimension. If I wanted to add any more dimensions or constrains Inventor wouldn't let me cause that would overconstrain the sketch. In my 2nd post there is this file attached. Guess I'll attach it to the original one as well.

0 Likes

Anonymous
Not applicable

It looks like your existing construction is not vertical. Use the "Vertical" constraint to correct that.

 

Then click the "Coincident" constraint, hover over the middle of the 30 rad arc, click the green dot, then click the vertical line.

 

The angular dimension only constrains the lines to each other, so I'm thinking that you can grab one of their endpoints and still move them around.

 

 

0 Likes

Anonymous
Not applicable

And here is the picture with  the correct colors.

 

0 Likes

JDMather
Consultant
Consultant

This is a case where I would either ignore the "issue" or do the part over from scratch.

 

I do notice however that the constraints seem a bit "odd" to me.

I have never used a Concentric constraint - coincident centerpoint is how I create concentric arcs.

 

I am not sure of why there is an sketch offset when Shell would do the same thing?

I would Keep Inventor Sketch Simple.

 

Here is my KISS Principle part.

Fewer dimensions.

Far fewer geometry constaints.

No trimming.

Same geometry.  


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


PaulMunford
Community Manager
Community Manager
Don't forget to turn on the degrees of freedom indicators when you see weird stuff in sketches to help diagnose the problem.

You can also use quick dimension. See which constraint it applies to help diagnose the issue.

 


Customer Adoption Specialist | Informed Design
Opinions are my own and may not reflect those of my company.
Linkedin 

0 Likes

PremTM
Advocate
Advocate

Hah, that kind of worked. It appears that line had horizontal costrain somehow. I had no idea it was possible. It was enough to delete that constrain and apply vertical one. I'll remove it anyway and set length and angle to another line since I want to be able to rotate it freely and change dimensions. Thanks to all who shared interest in resolving the issue! ๐Ÿ™‚

0 Likes

JDMather
Consultant
Consultant

In your image the line should have Horizontal constraint, not vertical.

 

In Inventor, the thick Axis is Horzontal, the this Axis is Vertical.

 

You are viewing the sketch rotated 90ยฐ.


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


PremTM
Advocate
Advocate

They probably are odd since I'm a begginer. However, here is my reasoning:

I start with the construction circle to set the distance of the first arc from the middle (or whatever centerpoint I want). The other way is to set coincident point for every arc + radius for each arc, like you said. I just think it's easier to read it with construction circle.

 

I don't think it's possible to make less geometric constrains. I need the symmetry, both straight lines have to be equal, all arcs concentric and the first arc is tangent to construction circle. All the other constrains are added by the offset command. All the dimensions seem to be needed as well, otherwise I won't be able to extrude it.

 

And what is Shell by the way?

 

And after saving the solved sketch and reopening it the problem returned but this time changing this one constrain won't work.

 

Well, I've done it as simple as possible now I suppose and it's still there and again, extrude works perfectly fine, no degrees of freedom, no missing constrains or dimensions, can't move any line. 

0 Likes

JDMather
Consultant
Consultant

@1234prime wrote:

 

 

I don't think it's possible to make less geometric constrains. .... 


Of course it is - I posted example.

I would not mention something not possible.

Did you open the file that I attached earlier?

Examine the KISS Principle part.

If you need to make some other logical adjustments - indicate what, why and when.


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


0 Likes

PremTM
Advocate
Advocate
Allright, I think I figured it out, at least as far as user may be concerned.
Turns out if you just change the dimensions of the outer arc to bigger (e.g. 30mm) it's gonna swap the color...I don't know why, I don't know what the threshold is but it works. So it's harmless, won't break anything, it's just annoying to see this thing for the first time.

Thanks again for your participation in this topic!
0 Likes

JDMather
Consultant
Consultant

@1234prime wrote:
Allright, I think I figured it out, ....

Forget all of your attempts.  

Open the file I posted earlier.

Do it right!


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


0 Likes

Anonymous
Not applicable

My appologies, what I thought was your "not vertical construction line" was actually part of a dimension. ๐Ÿ˜•

So this is my last ditch attempt to help. ๐Ÿ˜›

 

You said;

 

".... and the first arc is tangent to construction circle"

 

I don't see a construction circle (I double checked), but I do see 2 Tangent constraints. Are you sure you need them with the 3 concenctric constraints there as well?

 

 

0 Likes

PremTM
Advocate
Advocate

Yeah, I did not notice that file earlier.

 

What you did is how I got to work with the shape at my first attempt (except for the fact I didn't know about Shell command and needed to do hell lot of more to get it done without it) ๐Ÿ˜„ But then I wanted something more flexible (one-click rotation, changing all the dimensions easily on one sketch and to see the whole thing on sketch). I see why your solution might be better though. It's way less messy. Thank you.

 

Oh and when I deleted the outer arcs radius and worked on one constrain and dimension I think I solved the whole thing. It does not break anymore.

0 Likes