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Using "Offset" under Sletch Tools

Maavhamt

Member
I am creating a rectangular hole in a plate which is mapped from another part. I want to make the hole 0.5 mm larger than the mapped hole so I am using the Offset tool. This works fine but the resulting lines are red and can be moved using the "Select" tool. Do i have to manually go around putting constraints on the new lines? Also in parts it seems to have created a double set of lines, as shown:
upload_2018-10-23_11-14-26.png
 

RCH_Projects

Alibre Super User
This is all normal.

Resulting lines - Use the "fixed" constraint to prevent movement or create constraints to the source lines.

Source lines - Select the source lines and (right-click) "Convert to Reference Figures".

(Selection is sometimes simplified by left-click dragging a "selection" tool from left to right or right to left.
  • Left to right click-drag selects only figures fully enclosed in the selection marque.
  • Right to left click-drag selects all figures intersecting the selection marque.

How to Manually Apply a Sketch Constraint

Constraints can be manually applied to figures after they have been sketched. Sketch constraints can be accessed from the Constraints group in the 2D Sketching tab.

1. While in sketch mode select a constraint tool from the Constraints group in the 2D Sketching tab. The mouse cursor will change to display the chosen constraint symbol.

2. Select figures in the sketch to constrain. Many of the constraint types require multiple selections. For example, to apply a symmetric constraint first requires the selection of a reference line or sketch line then the selection of two more sketch figures. Clicking them one-by-one will apply the constraint. Only one type of constraint can be applied at a time, so the figures or nodes being constrained should be selected then the desired constraint.

NOTE: To select multiple figures or nodes press and hold the Shift key on the keyboard and drag a selection box around the figures or nodes. To delete selected figures and nodes from the Selected Figures list, press and hold the Shift key on the keyboard while clicking the figures and nodes.
 
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RCH_Projects

Alibre Super User
Well, CTRL-A and clicking the "Fixed" constraint is all it takes. Anything else requires presumptions by the software.
 

TimoCAD

Senior Member
Why not take the mapped sketch, create the hole. Afterwards take the direct modeling tools and do a pull face? ;)
 

JST

Alibre Super User
This just sounds like an attempt to avoid actually dimensioning things that need dimensioned.

If it is not dimensioned, it is free to change. And it WILL change in ways that you will not like, if anything is updated.

it is best to simply apply dimensions and not try to get the software to apply things.

Personally, I think I would eliminate most all of the "automagical" implied and "tiny symbol" constraints. Declare it, or do not declare it. Those "assumed" things seem to be more trouble than they are worth in many cases.

If the sketch becomes too convoluted then probably it is because too much is being done with one sketch.
 

TimoCAD

Senior Member
... it is associative as it is dimensioned. But not in the sketch it's in the offset feature itself. :)
 

NateLiqGrav

Alibre Super User
Personally, I think I would eliminate most all of the "automagical" implied and "tiny symbol" constraints. Declare it, or do not declare it. Those "assumed" things seem to be more trouble than they are worth in many cases.

Why eliminate them when you can already turn them off if you want?

constraint inferencing.png
 

JST

Alibre Super User
Same-same. "turn off"= "eliminate"

They are good in some cases, but not in all. I might turn them all off (eliminate them) but have not really checked into the consequences. Too busy doing the work to fiddle with it. I think I have turned some off, because they are not always applied.... never when I want them, always when I do not.......

But for offset, the subject here, they do not seem to ever be applied, so it is up to the user to declare intent
 

Maavhamt

Member
Hello yes thanks for asking. I had to manually constrain the "Offset" lines. I had a big problem because the hole was projected from another object as reference figures and I then superimposed solid lines. So when I followed RCH_Projects good advice I got 2 sets of reference lines hence to superimposed sets of Offset solid lines. So when I went to dimension it I found I had to move one lot of lines out of the way, delete them, then I could dimension the remaining set. Next time I'll find a simpler way of doing it. One learns by experience....
 

C.A.D.

Member
I hope that everyone will submit a description of the limitations they find with the sketch capabilities of this product. What this gentleman is explaining is a perfect example of something that needs to go to the top of the product enhancement task list. Anyone who has used competitive software knows these limitations but I can't seem to get this point across. I did submit a description of a similar item about 3 months ago. The person I was describing it too seemed to be ignorant of products like Solidworks and others. I'm sorry but I find it extremely limiting to either fully lock down geometry that you can't edit or use reference figures and re-create geometry and constraints as a work-around. As I explained when I reported my product suggestion was that I run into this limitation every time I model something (like 5 minutes in). I'm due for another year of support and I'd like my money to be well spent.
 
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