Sketch : defined or constraint versus fixed

[Anonymous]

Defined means sketch dimensions are locking the sketch.

constraint means position sketch against XYZ 000 are locked.

in this case locking/ locked means that without changing sketch dimensions the sketch is " fixed" .

what is the function fixed / unfixed in reference to defined and constraint

regards,

Pieter

[FrankCao]

Hi pghk51,

Thanks for the good question. 

When we say a sketch is fully defined or fully constrained, we mean the sketch has no degree of freedom at all. That if you want to add one more dimension/constraint to any sketch objects later, the solver will warn you that "Adding this constraint/dimension will over-constrain the sketch."

For a "fix" constraint, it is used to fix the direction of a curve or fix the position of a point. For example, you can add a "fix" constraint to a line to fix its direction. But you can still add dimension to the line to constrain its length. So in this case, the line is fixed in direction, but it's not fully defined or fully constrained because its length is still not defined.

One extra note I want to add is, if you turn on the option of "Sketch - color geometry based on constraint status", then all the fully defined/constrained sketch objects will turn BLACK. But there are one exception for curves. As long as the curve's direction is fixed, its color will also turn BLACK although it is still not fully defined/constrained.

Please let me know if you have more questions.

Thanks,

Frank

[Anonymous]

Hi Frank,

I am working on a shipshull.

therefore I did draw around 20 framelines  in Sketch

To be sure they are fully constrained I did dimensioning for a second time.

There are curves in the sketch.

I make use of the origin function ( left in browser) and snap in sketch palette to pick the correct points

But it will not turn black though F360 is warning for over dimensioning.

regards,

Pieter

[FrankCao]

 Hi pghk51,

Thanks for the question. Are you sure you have turned on the option of "Color sketch geometry based on constraint status" in the preference?  If this option is turned on, then it might be a bug for sketch solver. 

Could you help attach the file in this thread? Then we can go on analyze the problem in sketch solver.

Thanks,

Frank

[Anonymous]

It is turned on

and I can make fully constraint sketches

See also my latest comment on

item : Remove body ERROR

++++++ Remove body ERROR

The body error is not removed yet.

Meanwhile worked on the sketches to say the frame lines

Now they are all fully constraint

It has cost many hours to do

Learned about tangent and curvature handles.

These tangent points are quite tricky curvature handle and points can lay very close to tangent handle midpoint.

A lot of zoom to check if you choose the correct point for dimensioning @#$%^&*

Why is er no option in F360 when wanting (FC) fully constraint sketches for automatically detecting points with are blocking (FC)

Now want to find out what cmd LOOK OUT in sketch panel can do for me.

I see some dimensions change  colour but thats a flash ..............

Creating a face gives a distortion between two frames

Therefore I now creating a lot of water lines(WL)

 I will use these as rails

I'm getting really frustrated to make these fully constraint too. 

again : Why is er no option in F360 when wanting (FC) fully constraint sketches for automatically detecting points with are blocking (FC)

I didn't find it yet

I want have  the hull shape as it is given on the PNG drawings

I 'm going to create a face which I can use as start component for hull planking, creating frames.

every 12" there is a frame to be modelled . configuration is : 2x 12"frames , 1x 12"spacing  

Rudder Construction is removed

made one centre line (CL) sketch and one off (CL) sketch

+++++ Remove body ERROR

[FrankCao · Accepted solution]

Hi pghk51,

If you have turned on "fully constraint checking" and find the result is not correct, then maybe this is a bug in the solver. You can attach a model here in this thread or directly send it to weining.cao@autodesk.com. Then I will help log the problem and send it to our develop team to take a look at it.

Currently we only tell user whether geometry turns to fully constraint status by color(black). There is no extra information to help user fully constrain or not fully constrain the sketch. Usually user can try add/delete more constraints/dimensions to constrain or under constrain the sketch.

Thanks,

Frank