Assembling trouble,...

[cvriv.charles]

Hello again. Well,... I got a good grip on drawing parts. There's still alot that I dont know but with time as I keep on drawing I will keep on learning. But before I start my venture into the world of complex drawings,... I need to get the basics down.

 

Right now I am trying to assemble some simple shapes I made into whatever. But I'm having trouble understand the assembly process. Been reading through my book and it's only helping me out ehhhh. I actually figured more out just by playing around with inv on my own.

 

I know about the assembly constrain tool. But cant seem to figure out how exactly it works. So far it's not what I thought. GRIP SNAP is more like what I thought the assembling process would be. But still I am in the dark about a few things.

 

I was hoping that the assembling process would be similar to drawing parts. That being using the general dimension tools to tell INV exactly where I want things. But thats not the case.

 

Using the grip snap tool I was able to place a few shapes where I wanted them. I learned quickly that theres a difference between clicking a part first before using the grip snap and not click it at all before using that tool.

 

I am having some trouble with offsetting. I'll click the side of the part that shows the arrow pointing towards the direction I want it to go. I will drag is signify whether or not I want a positive or negative offset. I will then type in lets say .25",... when I click enter it's not .25". It does this everytime. I must be missing something.

 

Also,... using grip snap, is this a contraining tool? Is it the same as using the contrain tool?

 

I need to know how to place some exactly where I want it. It would be nice to have dimemsions like when sketching so I know where to put everything.

 

The example im working with now I have welding in mind. It's not like everything fits like a glove. Things have a to be positioned. I am assembling in a standard.iam instead of the weldment.iam. I didnt even try weldment yet because I though I would try that after standard too. But maybe there is something in weldment that allows you to place in a specific area with dimensions? Say the center of an end of a cylinder to a specific location on the face of a plate.

 

I looked for grip snap in my book and it's not even in there! And my book covers 2009!!! I paid 108 for this book and so far,... crap.

 

JDM,... you have some nice doc's on assembling/ assembly contraints?

 

Thanks. CVRIV.

[MarkFlayler]

Well, Grip Snap is not what it is cracked up to be, but is beneficial in some cases. It was added to 2009 but not heavily publicized and in my opinion not necessary for a newer user unless you are struggling with the concept. Read a little more about it here --> http://discussion.autodesk.com/forums/thread.jspa?threadID=725519&tstart=0

[MarkFlayler]

As for you work with constraints in general. One helpful tip I can tell you is to turn on your DOFs (Degrees of Freedom) so that you can see what parts have movement in which direction after applying constraints. Each constraint removes a different amount of these 6 DOFs (3 Translational, 3 Rotational) in order to constrain movement in an assembly. Turn them on by going to the View pull down and selecting it. You will not be able to create a contraint that conflicts with another as I am sure you have already found out. Here are some tips and tricks with the constraint Mate/Flush type and a little game I made for it. The PDFs and files are at the bottom of this blog post. --> http://rand.com/imaginit/1/rss/viewitem.asp?feedid=BLOGS_MFG_ALL&guid=476

[cvriv.charles]

Oh I got this!!! I figured it out. Can't believe I didnt pick it up right away. Makes perfect sense now! LOL. I was thinking at first that it was a one shot deal to get it into place. Where it actually took me three or so steps to get the piece where I wanted it. Awesome. This is fun lol.

[shift1313]

keep in mind your selection makes a difference as well. if you select a point, or a line, curve, face etc. also you can make constraints with planes.

 

If you are drawing(creating parts) in an assembly keep in mind that if you select the face of another part as your first sketch plane, this automatically adds a constraint and can be seen by expanding your model tree. Also the first component in an assembly is automatically "grounded". Right click on the component and you will see grounded with a check mark next to it. This means that your parts is essentially fixed.

 

If you decide to play with Dynamic Simulation make sure you go through the tutorials. Certain constraints in your model view will need to be suppressed and and created in the Dynamic Simulation.

[cvriv.charles]

Thanks dude! Some of that I knew already,... soe of it I didnt. I will have to play around with that. One thing I couldnt figure out was offset.

 

I mated two square plates together so that they form an angle of 90 degree. I then mated a triangular shape to the inside corner at the edge of both square plates. I had trouble oddsetting the trinagle so that it wasn't on the edge. When I specified an offset value the triangle moved off the plates towards the right. I tried a negative value and it still moved off the plates to the right. I want it to go left. When I viewed the DOF there was only one arrow pointing right. Im thinking thats why. But im thinking that arrow pointing right doesnt just mean the shape can only go right but instead moe left and right. Am I right? But how do I get the shape to offset to the left instead? I havent got that far in my book yet lol. Spent alot of time just messing around with INV instead. But seriously,... I learned more doing that then reading my book.

[cvriv.charles]

I'm having trouble with contraint offset. Still. I cant figure this one out. I checked my book and there isnt anything on it really. Just shows you how to create an offset. Doesnt go into detail at all.

 

It's weird because after playing around with it for a bit I learned that if I mate two faces together,... I can offset the faces in two directions by specifying a pos or neg number. But if I mate and edge with an edge I can only offset in one direction. Pos or neg value gives the same result.

 

Anyone know whats going on here? I attached a zip so you can see what the offset is doing. Thanks.

[shift1313]

i didnt look at your file cause i cant open it at work but if you have a triangle you need to constrain to two plates, i would just add coincident constraints(no offsets). Is this lined up on the edge of a part? if so you can do it with to constraints, if not i think you will need 3. Ill draw something up real quick.

[shift1313]

alright here i did it using faces and an offset for the third constraint. I started with a coincident constraint placing the faces of the triangle with the faces of my plates(which were already constrainted). Then i added a mate selecting the two faces shown(take note of the direction of the arrow and your Solution box. The last picture is the same mate just with an offset added in. If my solution box had the arrow facing each other the offset would have pushed them apart.

 

as a note, if you selected lines instead of faces for this same mate constraint you would have used two and it would have placed the gusset at the edge.

[cvriv.charles]

Thats it! You got it! Sweet! I understand now. This is awesome. Thanks!

[shift1313]

im not sure if there is a reference in the help file but its worth the time looking. play around with edges, faces and points.

 

Even if you arent going to use the dynamic simulation, going in there and checking out the joints may help you understand. There is a spacial joint that allows you to control all 6 degrees individually. There is also an animation showing what each selection and joint do. While these arent exactly the same as mates in model space the graphics may help.

 

Also creating mates and seeing how you can manipulate them in model space is handy.

[cvriv.charles]

Thanks a lot shift:) I will have to check that out. I'm install the content libraries right now.