Some simple questions about sketcher

[cadcam]

Dear All,

I have lived with a number of issues for a while and so I thought I would look to see if there are any options. However, currently can't find any links in the forum/wiki so wondered if someone could
point me to the correct location.

In sketcher with auto-constraints 'on' the system very usefully flicks up
constraints as they are solved. However

1) It doesn't seem to ever show 'perpendicular', which I often use when
sketching out construction lined etc. Is there a way to activate it to snap/be
shown?

2) I would also find it useful to automatically constrain to midpoints and
possibly even 1/2^n and 1/10 points. At one point there was a midpoint on the
wiki, but it seems that now it is suggested that it is a two stage process,
link to line and then symmetry, while possible it is not as quick when
constructing geometry with polylines. etc. Is there any work around/macro that
can be called with a shortcut (e.g. 1 -> 1/10s, 2-> 1/2,4,8.. )while still drawing?

3) When a drawing operation is finished the active constraints seem to be
shown on a black background, I assume to help visualisation.

a) Is there a way of showing the background when still drawing?

b) Is the background colour adjustable (I don't seem to be able to set
it from the preferences page

c) If drawing with the grid, it is rendered over the geometry and the
constraint icon/background. Is there a way of forcing it to the back?


Not directly related to the above, and it may be my memory playing up,
but I am sure at one point I had much thinner lines in sketcher. Is there a
setup I have overwritten in my latest install?

Many Thanks for any pointers.

[Shalmeneser]

1) It doesn't seem to ever show 'perpendicular', which I often use when
sketching out construction lined etc.

Never because impossible.
Auto-constraint is just for one line, so only vertical or horizontal.
If you use Sketcher_CreatePolyline, then it is possible because this object create polyline and (key M) you can perpendicular-constraint two successive lines in the same tool.

[Shalmeneser]

2) I would also find it useful to automatically constrain to midpoints and
possibly even 1/2^n and 1/10 points. At one point there was a midpoint on the
wiki, but it seems that now it is suggested that it is a two stage process,
link to line and then symmetry, while possible it is not as quick when
constructing geometry with polylines. etc. Is there any work around/macro that
can be called with a shortcut (e.g. 1 -> 1/10s, 2-> 1/2,4,8.. )while still drawing?

* 1/2
** you create a point (white or blue) (outside the line because otherwise it will be over-constrained)
** you symmetry-constrain with two points (or just the line) and your last point
** this last point is midpoint

* 1/10 : useless . Give me an example.
** You can use Sketcher_RectangularArray to repeat the same construction. Reference lines will be added with Equal-constrain.
** With Sketcher_CreatePolyline, you can do tangential lines. You select them all (selection box (right to left)) and Equal-constrain them.

[cadcam]

Never because impossible.

Is that because it is not being calculated? When a line being constructed approaches another it displays/jumps and shows the coincident icon and if the line is near vertical/horizontal, as you indicate, those constraints are shown, but not if the attachment is close to perpendicular. Is there a fundamental reason the solver can't identify such a constraint on the fly?

Regards

[cadcam]

* 1/2
** you create a point (white or blue) (outside the line because otherwise it will be over-constrained)
** you symmetry-constrain with two points (or just the line) and your last point
** this last point is midpoint

Quite long winded compared with just sliding the point of contact along a line until mid-point constraint is highlighted.

* 1/10

Example, Distributing holes along a line (ideally would also work with curves/arcs/perimeter etc).
Provided the constraint is remembered the number of holes etc will remain even if the items is parametrically changed. If working on a arc/circle an alternative way of distributing points/construction lines etc around standard
angles. [I know you can also sketch a polygon for a circle, but more difficult for an arc]

Regards

[Shalmeneser]

Never because not calculated.

* Internal constraint : vertical or horizontal
* External constraint : point coincidence (on point or object)

It's true that it could be calculated but for the moment, ...
If you want perpendicular lineS, you use a tool to draw lineS.
If you want a new line perpendicular to other, you constraint it. Perpendicular constraint is more general than just for 2 lines.

[Shalmeneser]

Example : Distributing holes along a line

Use Sketcher_RectangularArray :
* create a circle
* select circle
* RectangularArray (10×1)
* Modify Angle, Length

Example : Distributing along a path

Use Draft_PathArray

[chrisb]

2) I would also find it useful to automatically constrain to midpoints and
possibly even 1/2^n and 1/10 points.

With Polyline draw 2^n or 10 straight continuing lines. This will add tangent constraints to make them collinear. Then make all lines equal in length.

3) When a drawing operation is finished the active constraints seem to be
shown on a black background

This is a visual defect when Qt is running aout of some resources

c) If drawing with the grid, it is rendered over the geometry and the
constraint icon/background. Is there a way of forcing it to the back?

Not many of the pros use the grid in sketcher, as it is only an editing aid. It does not fix anthing from the sketch.

but I am sure at one point I had much thinner lines in sketcher. Is there a
setup I have overwritten in my latest install?

You can always reset your preferences with the reset button in the preferences. Another possibility is to delete your config files or to move them in case you want to restore them.

The sketcher setting Display->View scale ratio influences the line thickness.

[run_the_race]

b) Is the background colour adjustable (I don't seem to be able to set
it from the preferences page

From the Menu go "EDIT" -> "Preferences", then the "Display" icon on the left, then the "Colors" tab, then modify background color. I have a simple plain colour instead of a gradient:

BG.png (61.02 KiB) Viewed 890 times