Autodesk Inventor

[#1]

for some silly reason all of a sudden when i create a circle on the origin  it is not turning green and constraining the circle to it. Also when i am creating a line from the midpoint of another line the midpoint is not turning green and the line is not constrained to that point. Anybody have any ideas? I have checked the autoproject origin box in the appl settings and it is active.

[#2]

Check that your Constraint Persistants and Constraint Inferance have not been turned off. Enter Sketch mode, from the Constraint drop-down menu make sure that they are selected.

[#3]

i have checked the persistence and it is on. Anybody else?

[#4]

In the same "Constrain" pull-down, click Constraint Options and verify that coincident and midpoint are checked. 

[#5]

In my constrain drop down box i dont have an options button.

[#6 · Accepted solution]

While in sketch environment right click in the graphics window and select Constraint Options.

[#7]

Does the attached image help?

I have been having similar problems, but it is quite random and only seems to happen at certain zoom levels. Sometimes I'm able to attach to the midpoints etc... as per normal, and sometimes the mouse becomes a little erratic and I cannot always select the point or line directly.

Although the points usually do show and change color as expected.

[#8]

it was the contraint options. for some unknown reason all the options had become unchecked. thanks for the help.

[#9]

right click --->constraint options ---->select all ----->apply.