Pattern on Path - Not Following Path

[ruebarb.jason]

The pattern does not follow the path, the path was created by offset then I tried with just straight lines and 2 point arc, same result.

I've tried this with features (opt/id/adj) and bodies and I get the same result, looking for suggestions, thanks

[g-andresen · Accepted solution]

Hi,

From your screenshot on the right, I suspect that the position of the first instance is not identical to the starting point of the path.
This leads to such results.
Simply change the starting point or place the beginning of the path on the first instance.

günther

[TheCADWhisperer]

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

[ruebarb.jason]

Thank you very much, that fixed it, I didn't realize the pattern and the path needed the same starting point.

[Anonymous]

Hi Guenther,

I seem to have a similar issue, however, with me, the objects to copy along the path are placed at the center of the path and ON the path. I would like to create a symmetrical pattern, but this fails. The following I notice:

1. Fusion seems to calculate the path from the left instead of starting in the middle and going symmetrical.
2. The "Starting Point" field behaves strangely:
   1. Any value except for "0" and "1" makes everything disappear.
      
   2. Each time your switch between 0 and 1 the orientation of the pattern switches.
      

It seems, the Starting Point field behaves more like the "Flip" checkbox known from other commands.

Comment from my side: Other commands use the term "Offset" to shift things left/right. Unfortunately, in Fusion 360, the creativity regarding terms and, sometimes, design of dialogues seems to be very large. - I urge you to have a UI designer look over things and unify them.

Back to the topic: How do I make the pattern follow the path?

If you got the time, could you please explain the background to what is important with patterns on path. I watched your other screencast but without any explanations this is simply useless if you try to understand the workings behind things.

Thanks so much!
Thilo

[TheCADWhisperer]

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

[Anonymous]

Thank you @TheCADWhisperer ,
unfotunately my company guidelines do not permit me to pass original files. But the problem can easily be recreated:

So I have attached this simplified file instead.

Mark: The Start Point field turns red with any value apart from "0" or "1". You can toggle back and forth between these two. Every time you switch to "1" the orientation changes.

Would be great if you found a solution. Pattern on path is kinda a must-have...

Thanks again!
Thilo

[TheCADWhisperer]

@Anonymous 

Your sketch is not fully defined?

The first thing I will have to do is fully define your sketch...

When I start to fully define your sketch - first think I notice is that there are two lines where one line will suffice?

Then I see that the seed body is not at the start of the path and I quickly begin to lose interest...

[Anonymous]

Well, that was just a quick n dirty recreation. I figured it wouldn't really matter if that sketch is fully defined or not if the problem showed up. - And it did.

[Anonymous]

I've fully defined the sketch now. - Problem persists.
One line or two... needed or not... this is just a quick example not a multi-million-dollar project.

[TheCADWhisperer]

---

@Anonymous wrote:
I've fully defined the sketch now. - Problem persists.

---

No new file Attached?

Is the sketch for the path a separate sketch from the sketch for the body?

[Anonymous]

Oh, @TheCADWhisperer ...

Sorry, but I missed that one line of yours right below the screenshot:

1. Thank you for trying to help anyway.
2. Thanks also for making me look like a complete moron here.
   (Maybe I know less about Fusion 360 than you, but I do think the problem is clearly described and no-one here benefits from pickyness in irrelevant points.)
3. Could someone maybe please explain how a "Symmetric" option is supposed to work if the body is not in the middle of the path? My example clearly shows that Fusion does not simply mirror the path itself, as one might expect:
   

Sorry to all others for this de-tour! I still hope that someone will be able to help.

Cheers!
Thilo

[TheCADWhisperer]

See Attached file...

0 is beginning of path, 1 is end of path.  0.5 is midpoint of path.

[Anonymous]

Thank you @TheCADWhisperer ,

That is quite a revelation! So "0.5" works, too, for the Start Point.
(Why don't they provide a dropdown here like for the other settings? I wouldn't consider 0.5 to be intuitive...)

Anyway, I can reproduce what you came up with. However, in my example it only works if you select "Extent". Once you switch to "Spacing" all patterned copies disappear.

Strangely, if you use that slider within the sketch instead of entering values into the dialogue, then you see something again. Just nothing really helpful.

Do you have any idea on this?  (File attached)

Thanks again.
Thilo

[g-andresen]

Hi,

Can you check if the "Path direction" option works as well?

I have only chaos in the area of the arcs.

günther

[Anonymous]

Dear @g-andresen ,

Thanks for jumping in here! The objective is actually to use the "Symmetric" setting under "Direction" since I have an element that should be exactly centered.

However, I can switch to "One Direction".    (Still working wih my last sample file I uploaded above.)
Starting with the element in the middle I get the following result:

I may not set a negative Distance then to go in the other direction. The field turns red then.

But now things are getting funny... I am tweaking the "Starting Point" field ...

1. All values between 0 and 1 seem to be allowed. They stay black.
   (Again, I would rename that field and maybe use a percentage. Although an offset distance would definitely be more suitable.)
2. Values outside of that range turn red.
   But...
3. ONLY the exact values of 0 and 1 deliver results.
   Event with 0.5 all elements of the pattern disappear.
   
4. This time, 0 and 1 flip the direction of the pattern.
   

Right now I am utterly confused about how these settings work together. I have the feeling that the usability of this dialogue is far from intuitive.

For now, I have helped myself with the "standard" approach of starting at one side of the path with a fixed setting. However, I will need to be able to tune the spacing and number of elements later, preferably with the customer present. - So I'd be pretty happy if "Symmetric" in combination with "Spacing" and a centered source body would work.

Thanks to y'all again!
Thilo

[TheCADWhisperer]

---

@Anonymous wrote:

That is quite a revelation! So "0.5" works, too, for the Start Point.

(Why don't they provide a dropdown here like for the other settings? I wouldn't consider 0.5 to be intuitive...)

---

It is a ratio.

The path has a certain length the arc lengths + the linear lengths. (In my example you can see the calculated length of the path in the Pattern dialog box.  (Didn’t you wonder were I came up with that number?)

The beginning of the path is at 0% and the end of the path is at 100%.  Halfway along the path is 50% (0.5).  Now this path is only lines and arcs.  Imagine it was a Spline.  
Measure the distance between the instances (compare two on horizontal path to two on arc path out to 8 decimal places).

The Plane along path works in the same ratio way. 
Can you cite example of another dialog box to use for consistency in the UI for these two commands?

[g-andresen]

Hi,

With the option to create an arrangement symmetrically on the path (starting point 0.5), there is currently no way to align features on the path direction.
If you want to have an instance in the middle, you can also achieve this by creating the pattern in one direction from start point 0, positioning the first instance there, and making the number of instances odd.

Screencast

günther

[Anonymous]

Thank you @g-andresen for your clear answer. Of course this doesn't make me happy but at least we can get back to work(around)    :-))

Thank you too @TheCADWhisperer. The basic math of percentages is well-known, I guess, but your discovery helped a lot.

Since you've asked how to unify/improve the dialogue...

1. The field "Starting Point" gives NO help on which values to enter there.
   This could easily be solved by adding a mouse-over or some clear explanation below or behind the field.
2. Personally, I find 0.....1 in decimals as a fraction of the path length calculated from the beginning of the path to be VERY much NOT what I would EVER think of in this context!
3. Even a clearly labeled percentage of the path length would be very UNhelpful, I think.
   (Whisperer, you mention yourself how complex a path can get. - So how shall a user sensibly calculate the correct value to enter?)
4. I'd propose to change this as...
   1. Label the field "Offset".
      (A different example, closely related, would be the Extrude dialogue. This nicely uses offsets.)
   2. Enter value as a distance.
   3. Preferably allow the user to click on the path and snap to the typical positions.
      (start/middle/end of each segment, points...)
      The system could calculate and enter the corret distance then.
   4. Alternatively, provide a dropdown (as in the Extrude dialogue) to select from
      1. Beginning of path
      2. Offset distance along path
      3. At object
         (This would display the typical select box or "1 selected" and the X to delete selection)
   5. Add a "Flip" checkbox.
      (This would flip start and end point of the path and, thus, all references to these.)
   6. Of course, "Symmetric" is a setting which simply has to work.
      Important, I think, is that this should apply to the number of copies of the source object made by the tool.
      The path itself should NOT need to be symmetrical!
      Odd numbers of copies will, of course, have one element exactly at the starting point.
      Even numbers... Well, they should probably have the middle of the middle gap at the starting point. But what shall be done if the source object is actually already placed there? Will this be moved then? Will it stay and add to the number of copies, eventually making it an odd number again?

This last questions brings me to the question IF the source actually HAS to be ON the path... I think it might be very helpful if you could choose just ANY source from anywhere, pick the reference point and then the tool would place all copies along the path. Then, of course, even numbers in symmetrical arrangement would have a gap in the middle.

Just my two cents here.
Have a good weekend all of you! And thanks again for your help.

Thilo

[g-andresen]

Hi,

I am only posting this overview here once again.

Maybe @jeff_strater or his colleagues can explain this behavior?

günther