Construction geometry

denis_lp

Hi
Is it possible to create construction geometry which is not plane at the part level? For example construction points, lines, etc..
For example when I create a plane by using point and line at the part level, only obvious corner points can be selected - but what if I need a center of the circle?
Thank you,
Denis

Narayan_K

@ denis_lp, You can project that circle and use the center point as reference.
Please see below example as you mentioned,

3dcad

@denis_lp Yes, you just need to first select construction icon and the the geometry you wan't.

Note that Onshape can handle sketches that have open figures and multiple shapes because you can select only a certain part or figure to use for extrusion. So construction lines are only for you, Onshape does not require them.

3dcad

Difference to other mcads is that this:

is actually same as this:


the difference is when you create extrusion, you just select part of sketch from modeling area instead of the complete set from feature tree


and the real beauty of this system is that you can create multiple extrusions (parts) using different areas of single sketch!

andrew_troup

I don't pretend to understand the original question.
For example, I have had no difficulty picking the centrepoint of a circle to create a "Line Point" plane, and it's not clear to me how this relates to "construction geometry"
(perhaps the OP considers construction planes to be a type of construction geometry, which is not conventional terminology but is nevertheless arguable) ...

but one thing I would add to the answers is to clarify what is special about construction lines: they are NEVER used by the application as outlines for extrusion, rotation, lofting, sweeping etc.

Hence one way to use them is to ensure that there is a single unambiguous profile in a sketch, which means that the sketch profile can be selected by a single click on the sketch name in the feature list, or a single click within that profile in the graphics area, rather than (if the extraneous lines were solid) needing multiple clicks in the graphics area to identify the desired contours.

Another way they can help is to make it visually clearer to the user which lines and arcs in a sketch are included purely to help locate or reshape other entities. One example would be a line which serves to define the tangency of a spline entity.