Center angle

yan_sim

Hi !
I'am trying to center my angle of 45 to be centered with the mid-point.
Like in this tutorial ; Introduction to Sketching - Dimensions | Onshape Learning Center

If I change the angle in the dimension, the bottom line stay in place and only the upper line move.

https://cad.onshape.com/documents/2eaf3ff4b9635d15627aef40/w/112961f7952075f4cca700ee/e/1e419a991ae2c31eca54143c?renderMode=0&uiState=657b766b349eff6a884b5e8c

(Hope you understand, english was not my native language)

Thank you

eric_pesty

Add a vertical relation between the two end points:

robert_scott_jr_

If you want the pink line to stay in one place, you must give it an 'instruction' to do so. There are many entities in your sketch that are already in black. They are in an assigned position via a constraint or dimension. Even though your pink line is perpendicular to another line it is free to revolve around the circle's center point. Because you have given the pink line a perpendicular constraint and a dimension with the other two lines, they are forced to move with the pink line. Give the pink line an 'instruction' as to where to stay; the 'instruction' must be from a constrained (black) entity (or an origin).

As an example, In the document linked below I have added a dimension from a vertex within the three lines (they are attached to one another by the perpendicular constraint and angle dimension) to another vertex not associated to the area we are working with. I could have picked one of many entities (such as an angle dimension between the pink line and one of the other black colored radii you have already created).

- Scotty

https://cad.onshape.com/documents/e08abeed0ee89f1ad4f99b4e/w/728f3eb8713da3bd6429e7ff/e/b13395367b849c40e45134ba

eric_pesty

Add a vertical relation between the two end points:

yan_sim

Thank you, this is so simple !

If I can, I have another question.
I made another angle and want the the middle stay at the same place. I cannot use vertical or horizontal relation in this case.

I have put 2 lines with equal relation, went I change value of the angle both side are always equal, but the middle point move.
I have try to "fix" the middle point, it's work, but got error.

eric_pesty

The two equal lines work fine,  you could do a single line between the two points and make it perpendicular to the middle one or with its midpoint coincident with the middle line, these will all produce the same result.

The "fix" relation is overdefining your sketch as the point is coincident to the circle so it is trying to override the diameter of the circle.
For this, don't use "fix" on the middle line, rather set the angle of the middle line relative to some other reference (like the top plane for example) using a dimension or some other relation.

yan_sim

I have made a line perpendicular to the middle
when I change angle, the blue line stay at the same place and the middle line (pink) and the other side move.
What I want is the middle line stay at the same place and both side move. 

Thank you

robert_scott_jr_

If you want the pink line to stay in one place, you must give it an 'instruction' to do so. There are many entities in your sketch that are already in black. They are in an assigned position via a constraint or dimension. Even though your pink line is perpendicular to another line it is free to revolve around the circle's center point. Because you have given the pink line a perpendicular constraint and a dimension with the other two lines, they are forced to move with the pink line. Give the pink line an 'instruction' as to where to stay; the 'instruction' must be from a constrained (black) entity (or an origin).

As an example, In the document linked below I have added a dimension from a vertex within the three lines (they are attached to one another by the perpendicular constraint and angle dimension) to another vertex not associated to the area we are working with. I could have picked one of many entities (such as an angle dimension between the pink line and one of the other black colored radii you have already created).

- Scotty

https://cad.onshape.com/documents/e08abeed0ee89f1ad4f99b4e/w/728f3eb8713da3bd6429e7ff/e/b13395367b849c40e45134ba

martin_kopplow

Why not just use the mirror relationship on the two lines and the mid-angle line? It is only one click and no need for additional helper geometry in the sketch.

https://cad.onshape.com/documents/42746d38f6f5adc9c89c8f17/w/ce544a1c81fdf4e9ba1e1f64/e/83b1868b27f9df0bdf4c26c0?renderMode=0&uiState=657e03f1ef25594497e32f20

yan_sim

Thank you Eric and Scotty

I have added a line with a specific length, so the middle of the angle never move when I change degre

glen_dewsbury

Hey Yan. Just a small thing. You seem to want to keep the bisecting line and a connection line for dimensioning. Which works of course. The sketch can be a little cleaner using symmetry tool a dimensions from working planes. Just a thought.

https://cad.onshape.com/documents/b692ba672f837e71b65faba3/w/ccaac23887d50996264c013c/e/d9e7e65827015aba767f9edf
PS. Just a little OCD.