How to model this pattern?

[JosephLord]

Hi, I want to create four rib features around a cylidrical part. I would like to use an axis pattern to space them around the part, but they are not equally spaced. There are two that are 90 degrees apart, then two that are 95 degrees from these. Please see attached image. I can't find a pattern to do this and i don't want to model each one individually.
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[Kevin]

If it can be done with a pattern I think your only option is a table pattern.

[GunnarHansen]

1. Finish one rib with all drafts and rounds. 2. Copy surfaces of this rib to quilt Q. (use seed and boundary) 3. Copy Q, and Edit Paste Special and rotate 90 degr. 4. Pattern this with Table Pattern, 90 and 95 degr. 5. Solidify first quilt in pattern. 6. Ref pattern solidify. Sounds complicated, but is very efficient and stable for some redefines of rib. I use it a lot for pattern of complicated details.

[JosephLord]

Hi, I m unsure how to use the table pattern. I have opened the edit box, but where do you type to enter the values you require?

[JosephLord]

I have tried copying the geometry, and using paste special. I can then enter an axis dimension to place the new rib at the angle I want. When I edit the original rib and the other features that were copied, the rest update automatically, so I think I will use this.

[GaryFoord]

Hi, another quick & simple way to do this if all ribs are identical is to: 1. draw 1st rib with all features & create radial plane through its centre & centre axis 2. pattern rotate first rib 95deg anti-clockwise around centre axis to create 2nd rib 3. draw datum plane at 45deg to radial plane 4. mirror copy pattern to create 3rd & 4th ribs cheers

[GunnarHansen]

1. When using mirror be sure of the design intent: Is it OK or not that the shape is mirrored. Also do you get the dimensions you want? 2. I have bad experience with mirror, since it locks for changes of references in the original features sketch. So never mirror a feature with sketch! 3. We have WF3. Here it is not possible to copy, mirror a group pattern. Only a feature pattern. Which version do you have, Gary?

[GaryFoord]

Hi, in response to Gunnar, the method I mention is based on using WF4 M070. This version lets you mirror a feature pattern. Of course if the rib is not fully symetrical, this mirror method is not an option. Regards

[GunnarHansen]

Hi Gary WF3 also lets you mirror a feature pattern, but not a group pattern? What about the mirror situation? Has it become any better in WF4? Or can you still not change references in the original sketch?? Best regards Gunnar PS: Josef, have you found out the pattern table?

[JosephLord]

Hi Gunnar, I have looked at the table pattern a little. I have tried some simple table patterns on a simple part which worked, but you must have a angle dimension to select from the sketch? What if I have drawn the rib on the right plane for example, there is no angle dimension to choose, so how can you make it revolve around an axis at irregular spacings? Also, sometimes the pattern seems to go in strange directions.. As I mentioned, the rib is only simple, so I have used the copy and paste special. This is quick and easy for what I am doing.

[GunnarHansen]

Hi Joseph Please read the instructionsabove very careful: You must do the surface copy first. The angle dimension will come from the paste special, where you give the rotation angle. After the paste special you will have to table pattern just two more lines in the table with the actual angles. If you add a radius on the rib it will update automaticly. Just remember to put in the radius before the first surface copy, and use seed+boundary for selection of the surfaces. I promise you will be glad for this technique. Works similar for translate copies. Regards Gunnar

[Kevin]

If you still want to try the table method, instead of using an angle dimension from the sketch, create a plane feature through the axis of the part with an offset angle from the right plane (you ca specify an offset of zero. Create the rib feature on this plane. You can then group the features and create the table pattern or pattern individually creating reference patterns.

[ArisTroulis]

You have to sketch your first feature on a datum plane created from an axis and an agle constrain on the fly (means when you are inside the first feature creation you create the plane) this will give you the angular dimension you need. Then use pattern table to patern in different angles. If you want to include rounds in your pattern make sure to use edges from the feature you pattern and group them together before the pattern.

[JosephLord]

Thanks for that. I have created the rib with a short 5 degree revolve using an imbedded plane set at 0 degrees, and I can select this to set the angle of each instance. There seems to be a little error. You know how any cylindrical surface on ProE actually has two surfaces which you can selct independantly? Well, If the table pattern stays within one half of the cylindrical surface, it is OK. But if it extends onto the other half of the surface, these instances jump away or towards the axis. Seems a bit strange. Does this mean I can only do a table pattern less than 180 degrees?

[JosephLord]

Actually, I have fixed this problem, but it is not perfect. I had used 'use' geometry off the model to draw some lines of my rib. It seems these lines are only linked with one half of the clylindrical surface. I re-drew the rib completly independantly of the model (no converting model edges to use as lines) and I can now do 360 degrees of irregular spacings. Still, seems a bit silly. Why do cylindrical surfaces have to be in two halves...

[GunnarHansen]

Hi Joseph You should try my method?!?!! It should solve that silly problem too. Also, if there a many complex "ribs", or whatever, this method gives a faster regenerate. I know its something of a workaround compared to table pattern or group table pattern directly, but it works for me... At least give it a try, and let us know your opinion?

[ptc-1972305]

Joseph, I faced the same problem in past. I don't think you can do it by any pattern without calculating angle. Why don't you do as separate features? I mean draw all the ribs separately. At that time you will have to use 4 times rib dimensions. To fix this problem you can give relation for them. Regards, Vimlesh.

[GunnarHansen]

Vimlesh Because every time there is a change he would have to do it 4 times. For example if a radius is added to the rib. Has somebody tried "my" method?

[John.Pryal]

Hi Joseph, i think your orginal thinking was the simplest approach, model one rib & pattern it using axis pattern feature, you need to take 72 instances (every 5 degrees) & blank 68 ribs leaving the 4 you require. Does that make sense? Regards John

[mjcole_ptc]

Results in FamTab model

[TomD.inPDX]

or...

[TomD.inPDX]

...more interesting titbits when using Point Patterns:

This works fine with a point pattern. I did learn that if you make the circle in the sketch to manage the points a construction circle, the pattern does not rotate. the pattern follow the points, but the ribs all orient the same way. When I changed the circle to geometry, the pattern followed the normal of the circle as expected (desired). For some reason, it would not except the disk's outside surface, even if I removed the taper.

I did have to use the alternate origin so I created a datum point while inside the pattering dialog. This corrected an odd Z-offset issue that seems to be prominent with pattern origins.

Notice how the entire definition remains within the dialog.

Of course, this is Creo 2.0. I am not sure how close to this you can come with WF but the end result should be possible with the tips included here.

[mjcole_ptc]

Another option probably the easiest as long as the two outer spacings will remain the same at 95deg ,ould be to use a 2direction pattern +95deg as angular spacing in direction 1 // then -185deg in direction 2.

1 pattern feature no tables or complex editing, but if you decide you want 3 angles 85 90 95 then the other methods may work better. paste special allows you to keep all the features identical except for spacing angle which will be controlled by each pasted feature

John, Skipping 68 ribs in a pattern sounds like a design intent and rebuild nightmare but it'd work. there wouldn't be a need to pattern the full 360deg around just 280deg with total of 56 instances

[mjcole_ptc]

So in my post from yesterday I suggested doing a 2 way or 2 direction Axial pattern forgetting that only Dir1 is axial and Dir2 is Radial so that is wrong or impossible.

Today I also tried out a modified version of john pryal's suggestion along the 280deg of 360 and unchecking Boxes points for unneeded locations.

With that mithod which I'll update on the 21st or tonight I used a workaround to prevent the flip and section fail that occurs past 180deg angle using a sketched line.

[TomD.inPDX]

Although this is an old thread, (very old!) it is still interesting. Some people have done amazing things with dimensional patterns. The one that I would like is also related to dual rotation vectors. All to often, my patterns want to be rotated twice for the "to" location/orientation. You can do this with paste special, but I haven't found how to create the feature to allow this in patterning.

This was one version that was once posted here:

...where 1 direction uses 2 parameters. But if you had two angle parameters in the feature, one would think that you can then pattern the feature using two rotational vectors. My brain just doesn't think of how the feature would have both these elements in them or even how to have the foresight to create them.

[mjcole_ptc]

Dim Pattern for internal PL8 plane
Direction 1 -95deg Right Hand Rule Light Purple arrow

Direction 2 +185deg Right Hand Rule (95+90) Dark Purple arrow

ROy GBiv in that order going ro make body yellow but left it gray

my method for dim pattern was successful

Michael

[TomD.inPDX]

After I posted the last one, I stumbled onto this options...

Adding a 3rd dimension to the direction alters the feature's size. The 3rd dim on the rectangular slots was added as -2, and in the one being shown is the diameter of the hole changing along the pattern.