constraints not working in correct direction from 0

[samspade]

I have a simple iPart - an extrusion with 4 sets of holes on it. I constrained the patterns a specified amount from 0 down the length of the part. for some reason, the last 2 sets of holes keep going in the opposite direction so end up off the part giving me an error. 

Note: I am driving the part with excel, and I have the patterns set up to suppress if the distance entered in excel is 0 (as they are not needed for that particular part)

I don't know if this is enough to get any help here, but if it rings a bell I would be very grateful for any help.

thank you in advance for your efforts.

[swalton]

It would help if you can post the part, along with your Inventor version.

If not, can you make an example part with the issue, but without any proprietary information?

[samspade]

ok, here goes

[admaiora]

Hi,

can you attach parameter.ipt too?

[admaiora]

In the meanwhile,

I won't reccomend you to you dimension using "0" as imput.

You should prefet vertical/horizontal constraints.

[samspade]

THANK YOU!

[admaiora]

You have imported the beam geometry from AutoCAD, not the best practice (no parameters control+ danger of sketch destruction)
You can create a block inside Inventor, to reduce the 118 dimensions missing and improve a little the global picture.
I think that your design intent could be simplified in the workflow.

Instead of trying to understand all your workflow, a little twisted, I prefer to try to understand what do you want to obtain.

In the meanwhile here a sample i have uploaded now about suppression in iParts.

Consider that if you want to suppress something when a specified measure is set to a speciefied number or set to zero, you can use iLogic, that is very simple.

Let me know what do you aim to.

[samspade]

a little twisted? really? 

Thanks anyways. a person can be helpful without being demeaning. 

i have no training in this program and was looking for a little help. i think i will figure it out on my own rather than deal with this attitude.

have a great day!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[admaiora]

Calm, calm.

Clearly I was referring to the workflow, nothing personally.

And with "twisted" I meant "intricate" to understand.

From this perspective there is no reason to feel offended or read a "demeaning" message or "attitude".

It was just a technical help, no more, no less.

Everyone can improve, everywhere.

[samspade]

Certainly everyone can learn, but it does matter how things are presented. I have worked on this thing for a bit and i don't understand why one or two preps work then the wheels come off on the next 2 when they were created exactly the same way.

I understand it is hard to deconstruct someone's logic but it seems rather basic to me. Am I not supposed to use a rectangular pattern? Am I not supposed to use the properties of a prep to suppress it, when it is an option right there? and sometimes it works and sometimes it doesn't?

seems glitchy to me and I may have to work around all this. 

Sorry to get defensive, but this is just something i have put a lot in to and it is very frustrating. Makes me feel like Inventor is pretty easy to break, but i suppose after my experience with dynamic blocks in AutoCAD i shouldn't be surprised.

thanks and seriously have a great day. i am going to see Tom Jones so my night is bound to be great.

[admaiora]

As i said a zero dimension is a dimension to avoid, it' not stable.

It tends to flip (Inventor has a pure geometrical mindset).

Knowing your design intent, we can solve it a much easier way, cut to the chase, with a robust and streamlined design and solution.

iParts are not difficult, but they claim a good basic mastery of Inventor as Sketch, constraints/dimensions, parameters,  constructions, etc.

Paradoxically less you know about AutoCAD faster you will learn Inventor.

[kelly.young · Accepted solution]

Hello @samspade I created a screencast with a bit of rambling as I went, but I did find where you have the .000 dimensions setup within the sketch.

I would not recommend ever using a .000 dimension as it has the tendency to flip. Instead fully define the sketch point to a dimension and suppress it when not used instead of a zero location.

I don't have a good technical explanation, but experience has led me to stay away from that practice. Also refrain using the Fix Constraint which wreaked havoc on my models in earlier days (I didn't see any in your model but just an fyi).

Hope that helps!

Please select the Accept as Solution button if a post solves your issue or answers your question.

[samspade]

i did NOT put the .000 constraint into my sketch. I put the prep3 and prep4 features on the part but they were not required in the part so in the excel sheet i put 0 for the dimension.  i will in future lie about the dimension or some other thing. i will also read about iLogic to possibly suppress in a different way.

thanks.

[samspade]

kelly thank you for spending the time. 

we aren't making any assemblies, we are just trying to get cnc programming on these extrusions. I didn't set anything up for 0 in the sketch, i put (going from 0) the sill prep, prep1, prep2, prep3, prep4, head prep but i think once i put a 0 in for preps 3 and 4 (not all the extrusions get all the preps) it blew it up.  so i guess using 0 as the trigger to suppress was a bad idea. i will look into this. thanks for all your help you were very gracious.

[admaiora]

If insert a 0 value to a parameter, and the parameter is linked to a dimension, the dimension will be set to "0".

In this way the dimension will flip.

You can use a plane projected (planes have a versus) to avoid that, or iLogic.