Linear Pattern suppression of features

I have a number of holes that I repeat with a linear pattern "n" times.
Between the holes I have a smaller hole - this I repeat "n-1" times (because
it sits between the larger holes.

Is there a way to use the same linear pattern on both holes and then
suppress the last repetition of the small hole?

 

Select the "instance" that you do not want and hit delete.

Richard

 

How do I "select" the instance? (I have tried to click on it....)

If I make 4 repeats and delete the 4th instance of the smaller hole - can I
then change "n" to e.g. 8 - and then still have the 8th instance deleted -
or did I delete a the 4th instance specifically?

Steve

 

Select the face of the hole, it should highlight. Hit the delete key and a
dialog box will give you the option to delete the pattern or the selected
"instance".

You deleted the specific instance.

Richard

 

If I make 4 repeats and delete the 4th instance of the smaller hole - can I

I am pretty sure you are just deleting the 4th instance. If you later
change "n" to 8, the 4th instance will still be deleted instead of the
8th instance as you intend.

I think the best method of truly automating your pattern is to use 2
separate patterns and then use equations to drive pattern #2 from
pattern #1.

 

You could have a similar result using Equations.

double click the second pattern select the dimension that is the quantity
tools>Equations
add
double click the first pattern select the dimension that is the quantity
type " - 1"
now your second pattern will always have one less than your first pattern.

I have used equations for pattern quantity to fill a length of thread.
we cut revolve the first thread and then pattern it.
so the equation is
Qty@Pattern1 = 2 / Offset@Pattern1
this will make a pattern that is less than one thread width from 2" long.

Corey

 

Yeah thought so.

I have a part that comes in different lengths - i.e. different n-value, and
it is always the last small hole I need to delete.

Equations - that's new territory.... so right now I have just made two
Linear Repeats.

Steve

 

I would strongly recommend you check out the equations if you want you
patterns to automatically update. They really are pretty simple to use.

Basically, you would do the following:
Create you first linear pattern n1=8, d1=2"
Create your second linear pattern n2=7, d2=2"
now create the driving equations:
n2 = n1-1
d2 = d1

You can also create equations to automatically center your pattern
and/or automatically calculate the number of instances to fill the part.

If you wish, I will post an example part that uses patterns and
equations as I have described above.

 

This is so simple, maybe it's not a good idea, end of the day and all that.

But, if you dimension your part from the other end then you could always
delete the first instance of the small hole!?!

HTH,
Muggs

 

.....how apparently obvious!

But it doesn't work - I just tried it - deleting the first instance means
deleting the feature to pattern - i.e. all the following instances are
deleted.

Maybe there's another way of deleting the first instance without deleting
the actual feature.

Steve

 

The "Equations" menu is not active (shaded grey) under Tools. I place the
cursor in the #-field of direction 1, and try to select tools-equations -
but can't.

What do I do wrong?

Steve

 

When you have your part open, click on the "Sigma" icon in the Tools
toolbar - this brings up the equations box. Then you click "Add" which
opens the "New Equation " box. To add a dimension to the equation, you can
either type it in, which is prone to mistakes, or you can click on it out in
the graphics area. To get it to show in the graphics area, double-click the
feature in the Feature Tree. Then add the other parts like ( ), +, *, etc.

WT

 

Equations rule...!

How do I edit an existing formula? (just the one formula - not "edit all")

Can I create a variable and use it in many equations? (now I make the same
calculation in all formulas to derive my "n"-value)

Steve

 

Go ahead and select "Edit all" and this will open all for editing. At that
point, pick the one you want to work on.

I don't know for sure about the variable - others might. But, you may not
need it. Remember that the "n" value, which I presume is the number of
holes, is actually a clickable parameter in the graphics area. When you
double-click on the pattern, it displays it's information and just as you
can then change the number of instances for different configs, you can also
select that parameter to insert into your equation.

WT

 

Yeah - got that.

How about referring to values in other parts? I have an overall width upon
which everything else depends - so if I change it in one part, it would be
nice to have it cascade into all other parts.

Steve

 

Good thought - this, of course, being based on the "other" end.

WT

 

In a programming environment you would set a global variable that could be
used later. Here, I think the way you would do it would be to have the
length, holes, etc. defined in the context of the assy. Then you could have
it follow another existing pattern, or whatever. However, that might not
fit with your design or company structure.

WT

 

Thought of it - but my design is in fact not just "one large hole" it is a
while bunch of stuff that is repeated n times - and this way I would ahve to
create this "whoel bunch" twice + the "small hole" - so I evaluated the
issue about having double definitions versus two linear repeats - and chose
the latter.
Steve

 

If it is simple you can select the surface of the hole and right click
Somewhere in the menu there is delete face. if it is a hole it should fill
the hole and your first instance is gone yet your pattern stays.

Corey Scheich

 

I just tried creating a variable it only lets you assign a value to a
dimension. If you need a variable I would suggest adding a reference line
in your first sketch and dimensioning the length. Nomatter what equation
you add to it it will not affect the model untill you use it in another
equation. I was checking this in 2003 not sure about 2004. There may be a
more elegant way but this is what I would do until one surfaces.

Corey Scheich