Skeletal Modeling using 3D sketches problem?

[Anonymous]

HI everyone!

Why can i use lines from a 3d sketch to constraint a part to a skeleton base part?

I have attached a example where i try to constraint the tube.ipt using 3D geometry lines of the part  Layout_3d_sketch.ipt in the assembly teste.iam, but i'm unable to select any lines from that file.

Why can't i use this 3D sketch lines in a skeleton base part?

[MariaManuela]

Olá SMachado 🙂

You must use 2D Sketches.

If you really want to use these 3D lines with assembly constraints you must create a Work Axis on them.

[Anonymous]

Hi Dear Manuela!

Well in some cases it's easier and faster to use 3d skechtes ,and you dont have to create alote of planes.

Inventor should allow the use of the 3d skecthes for skeleton parts, what is the point creating addiotional geometry axes in a geometry allready created?

[MariaManuela]

Hi SMachado,

Yeeeessssss..... i really understand you perfectly but that's how Inventor works!

More people talking about it, take a look please if you can:

 http://forums.autodesk.com/t5/Autodesk-Inventor/Skeleton-modelling-3DSketch/m-p/605672#M56500

See you!

[johnsonshiue]

Hi! I am forwarding this request to development and product design for review.

Thanks!

[FProcp]

I think Inventor 3D sketches are not fully parametric.

You can put some dimensions on them but you Do Not Have Full 3D Control in x,y & z.

Maybe you could have a 3D Triad pop up when you select the end of a line (or a point) and then you use the 3D Triad to move/edit it?

Maybe the triad could give difference in x, y & z values from previous point (or any other reference point you select) and this would be powerful just like 2D parametric dimensions. You could drive the 3D sketch in full 3D moveability using this.

==

Does this sound too silly ?

[johnsonshiue]

Hi! Based on my understanding of how Inventor works, 3D Sketch is indeed parametric as is majority of commands in Inventor (except Move Face for example). Only very few are not. The triad is just a precise input tool allowing user to move around a sketch point in 3D, you can enable similar input tool in 2D too. In 3D Sketch, you can use dimensions and constraints to drive the sketch entities like in 2D.

Thanks!

[FProcp]

Please tell me Johnson, how would I move the end point of the attached 3Dsketch exactly 2mm in the z-axis and 1mm in the y-axis using constraints?

[johnsonshiue]

Hi! I look at the part you attached here. If I understand the constraints and dimensions in the 3D Sketch correctly, there is only one degree of freedom on the point, allowing it to move along the line. If you add a length dimension on the line segment, the whole sketch will be fully constrained.

Under these conditions, I am not sure how the point can be dragged in Z and Y.

Thanks!

[FProcp]

I give you permission to delete constraints if you require.

All I want is all the points, except the last one, to remain exactly where they are and the last one to move how I said.

I don't care how you do it. You can delete/destroy whatever you want. Just give me the end result.

[johnsonshiue]

Hi! It is certainly more laborious to add dimensions or constraints to get to the precise position than using 3D Move/Rotate tool.  In order to add dimensions or constraints, you first need to create a reference, because Z + 2mm and Y + 2mm has no meaning in Inventor. The quickest way it to figure out the position of Z + 2mm and Y + 2mm from origin. Then, create a UCS at that absolute position. Then use coincident constraint to snap the endpoint of the line to the origin of the UCS.

Certainly, there are many other ways to establish the reference like creating workplane, workpoint, and workaxis. But, the idea should be the same.

Thanks!

[FProcp]

Should be easy, in AutoCAD I could do that in about 3 seconds