rectangular pattern fails when using a parameter that is sometimes zero

[Julie_7]

I would consider this a bug, but in any case it is problematic for me.

I have a design that has an component that is parameterized to be some number of rows and columns of a unit size.

I change the rows and columns parameters and 3D print that variant of the component.

Here is a simple example showing a body with 2 columns and 3 rows.

The pattern is the combine of the foot being joined to the block. The block is always row by columns of a unit size. Everything works fine until I want to create a model with only 1 row or 1 column. This is the smallest version of the model and requires no actual patterning of the combine, which I believe should work.

However, if I set either rows or columns to zero then the pattern become an error shown in the timeline.

I can still print the 3D body at the new size.

But,

Most of the time the error clears when the rows and columns are changed and both greater than 1.

However, there are times when I have sent a model to the printer and after it printed realized that the pattern was changed (I don't know when it happens) and the count for one of the axis of the pattern had disappeared.

[jeff_strater]

Pattern works by taking an existing entity and replicating it.  If you do not want that entity replicated in a given direction, the count should be 1.  Zero is not a valid count for any pattern feature.  I'm not sure how to interpret a count of "0".  Should that, somehow, delete the original entity?  Fusion does not work that way.

[HughesTooling]

@Julie_7  You can workaround this if you enter something like max(Count; 1) as the parameter for your Axis 1 and 2.

Here's an example, Here count is set to 0 but CountX is 1. EDIT. Just tested and the pattern feature seems happy enough if you enter 1 for both axis.

[Julie_7]

I didn't explain myself correctly. I did mean that the minimum size of the body was 1x1 units.

[jeff_strater]

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@Julie_7 wrote:
I didn't explain myself correctly. I did mean that the minimum size of the body was 1x1 units.

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OK, so then, the minimum counts for any pattern should be 1.  It should work correctly.  Here is a model with a box, an extrude of a cylinder, and a 3x3 pattern:

If I edit the counts in this pattern to both be 1, we are left with the original cylinder only:

model is attached.

[Julie_7]

(I have been fighting with the web page trying to get it to not give me an error when uploading my example.)

Starting over, I have a model that will be 3D printed and in various sizes, based on number of X and Y units.

Looking at the image below, this has 1 x unit, and 3 y units. The bottom is patterned to have on foot for each unit.

The top is patterned to have one more nub than the number of y units and the side has a cutout that is patterned at 1 less than the number of y units.

When I want to print the smallest variant of the model, I set x_units to 1 and y_units to 1. This produces a model that looks like this.

With my actual model I get the pattern error but it correctly doesn't have the patterned feature at all. For some reason in this model I do get part of the patterned feature.

I also do not understand the difference between the three patterning options (optimized, identical and adjust).

Regardless, in all cases where I need to pattern from 0 to N-1 times based on the model dimensions I get this

Thanks for all your help!

[HughesTooling]

@Julie_7 What do you want in the bottom image? Do you still want half a star or no star?

Mark

[HughesTooling]

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@Julie_7 wrote:

Regardless, in all cases where I need to pattern from 0 to N-1 times based on the model dimensions I get this

Thanks for all your help!

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If you're happy with half a star you could enter max(y_units-1; 1) and it should not fail when the answer is zero.

[Julie_7]

Here is an image of the actual part.

You can see why I need zero in the base case of only one square. Today is it showing partial cutouts on the single unit dimension. That must be because I changed what I was patterning yesterday based on a different issue. Prior to yesterday there was no partial cutout and the body was correct, but the pattern in the timeline showed the error.

[Julie_7]

Here is another example.

When it is smaller than 2x2 there should be no hole.

(I am sorry. I am really struggling with the forum/browser. It keeps giving me errors, and changing screens and telling me that I have saved drafts that it won't show to me.)

[Julie_7]

no star

[jeff_strater]

I will ask my question again:  When you say you need "0" instances, do you expect that, somehow, Fusion will interpret this as deleting the geometry that was patterned?  In my example of the patterned cylinders, would you expect that a 0 count would delete the original extrude that formed the cylinder from the model?  If so, then pattern is not how you would achieve that result.  You need some kind of conditional feature execution, or a configuration tool.  Configurations is currently under development in Fusion, but is not yet available.

[HughesTooling · Accepted solution]

Fusion does not allow you to suppress a feature so the only workaround I can think of is to move a body you use for a combine cut off the body you're cutting.

Edit. Thinking about it a bit more, this will not work because you can't dynamically add bodies\features to a combine feature. Don't think you're going to get this to work automatically in Fusion.

So you'd need to create a body for the star for example and position the profile in a sketch with a dimension and move it off the part when you only have one unit. Testing with a combine cut it doesn't seem to complain if the bodies don't overlap. You can use the min\max parameters to position the star so it's moved off the body when the count is 1.

This will not work without error if you try using an extrude cut.

Mark

[Julie_7]

One additional thing I should mention is the reason that I am trying to design this way is that I use a script the varies the range of x and y units from 1 to 10 or more and saves the body as a 3D print to a file.

[Julie_7]

Yes, I mean when pattern evaluates to 0 I mean no instances.
Now that you say it back to me I realize that this makes no sense.
It did make sense to me back when I was trying to pattern bodies, but then I found out that after the pattern of bodies I had a bunch of individual bodies and no way to join them all.

I see that if I pattern a feature the feature has to exist first.

Thanks for being patient and explaining to me. I am a software engineer, and I often think that way. I am trying to learn to think more like a 3D designer but it is hard at times.

[Julie_7]

I think I just realized that my solution is going to require one body that is based on patterning that can use parameters to produce most of the sizes, and individual bodies for some of the base cases, such as 1x1 and 1x2.

Thank you so much for helping me understand how to think like F360 does.

[HughesTooling]

@Julie_7 Can you make a simple example design you can share here as an f3d? I'd like to experiment a bit but would be easier with a design working the way you are. I'm wondering if you could have a Extrude Join that would be positioned over the feature you don't want if the count is 1 but moved to an area where it would just be consumed into the main body if the count is more than 1.

Thanks Mark

[Julie_7]

The example model was posted above

[Julie_7]

Actually, I just discovered that Fusion 360 does allow suppressing a feature. I can right click on a feature in the timeline and suppress the feature and the following features are recomputed without it.