Question about Points during Scale Function

[krummeck]

Good Evening

I have for years battled with the scale function. Not the amount of scale, when I get there, but the point about which the design will scale. The videos I have watched on the subject a trainer will select the design to be scaled, randomly choose a point about which the design will scale and its scale amount, and its done. 

I have recently had a design with 74 points on it, (complex Design); not one of those points would select at the point required in the function.

I need to ask, what governs the points eligibility, and how can I use the correct point each time I need to scale something?

Please advise

Kind Regards

Warren Krummeck 

[TheCADWhisperer]

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@krummeck wrote:

I have recently had a design with 74 points on it, (complex Design); not one of those points would select at the point required in the function.

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[krummeck]

Cool, here it is....

[TheCADWhisperer · Accepted solution]

The sketch is poor quality - I would start by fixing the problems with the sketch.

Examples to follow in a minute...

Missing Tangents?

Blue geometry?

Missing Dimensions?

Unconnected points?

More overlapping geometry...

Would you like to learn how to do this correctly?

[krummeck]

Why did it distort so badly, or have you moved it around like that?

[krummeck]

Are you perhaps saying that only constrained points can be used in the Scale function?

[jeff_strater · Accepted solution]

first clarification:  it seems you are referring to Scale Sketch here, not the general Solid/Surface Scale.  Is that correct?

If so, then what you are seeing is probably an effect of Fusion's selection system:  An item cannot be selected twice.  So, if you window select the geometry to scale, it grabs points as well as curves.  So, all those points are now selected in the Entities selection.  So, they cannot also be selected for the Point selection.  There are numerous ways to get around this.  One way is illustrated in the screencast below - change the filter to select only curves for the Entities selection.  This works in your sketch because there are no "free" points in your sketch - all the points are attached to curves, and so will scale just fine.  Then, you have to go back and turn the filter back on to select a point to scale about.  Many people want to scale about the origin, so just avoiding that origin point in your Entities selection will work fine.

What @TheCADWhisperer is referring to is general sketch goodness criteria - it is always better to have your sketch more constrained than not.

[krummeck]

Wow that is awesome thank you. The secret revealed. When I am making up something that I feel should be around for a long time I try constrain it a bit more, bad excuse I do need to try harder. Anyway I will go look for theCadwhisperer youtube channel, considering he is so keen to straighten out my world.

Thank you again

[TrippyLighting]

Generally I would try to avoid the scale function. 

The sketch you imported is of poor quality and the "deformations" when trying to constrain the existing sketch comes from the fact that very little is tangent to begin with, and the sketch is of poor geometric quality.

I've re-created the sketch with proper dimensions and constraints:

Now you can change individual dimensions to get to the size you want.

[TheCADWhisperer]

@krummeck wrote:

 When I am making up something that I feel should be around for a long time I try constrain it a bit more, bad excuse I do need to try harder.

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@krummeck 

Actually, get lazy!

When you get the techniques of sketching mastered it is actually far less work.  I would have to work very hard to make the sketch as you did, but to do correctly is pretty easy (even @TrippyLighting (see Message #9) ) can do it.  😄

In general it is often best to do Fillets as placed features rather than in sketch.

[colinskaminski]

I often have to scale dxf logos from art software. They are a nightmare. I always scale them in their own document and choose the origin as the scale point. I often have to do an hour of repair to make it all work and rarely can I fully constrain the sketch. 

It can be done with patience if you have to.