how to center sketch

how to center sketch

Anonymous
Not applicable
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Message 1 of 15

how to center sketch

Anonymous
Not applicable

This is i'm sure an simple one but I have this model here

howto.PNG

I have 3 boards stacked on top of each other, and now im going to create a frame to wrap around it; I know the frame's length needs to be the full length + 2 * material thickness, which I already have that function done -- but my question is how can i tell this sketch to center on the 3 stacked boards so that the material thickness is extending evenly on both ends. All of the tutorials I've watched always encourage never to manually move things, etc so im assuming there's a functional way to do this?

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Message 2 of 15

davebYYPCU
Consultant
Consultant

If I have it right, the boards would be a centre rectangle?, will already be symmetrical.

 

If not, then Horizontal / Vertical to the midpoint of the board edge, would do it.

 

might help...

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Message 3 of 15

rohit.bapat
Autodesk
Autodesk

Hello @Anonymous

 

Thank you for posting you query. I have created a f3d file of my own based on your description. I am using length = 100 mm, width = 50 mm and thickness = 10 mm

I created stack of three such sheets. Now while creating the wrap sketch, I initially created a normal rectangle and then added dimensions according to the formulae.

 

Then used Collinear + midpoint constraints to center this rectangular sketch.

 

Centered Sketch.JPG

 

I have attached my f3d file for reference. I hope this will help.

 

Thank you,

Best Regards

 

Rohit Bapat





Rohit Bapat
Product Owner
Message 4 of 15

Anonymous
Not applicable

this looks like what im trying to achieve. Is there any make to make a screencast or perhaps describe in greater detail the steps you took after creating the 3 stacked bodies? I dont understand how to use those alignment tools on a body from a sketch. I must be missing something because when i try that it doesnt give me any points to align to

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Message 5 of 15

Anonymous
Not applicable

update:

 

When I did a similar setup again. I created my 3 stacked bodies on the top face, then from the front face, i created a new sketch for the front rectangle. after drawing the rectangle sketch, when I then click collinear and click the top line of the new rectangle, and then the top line of the top layer body, it gives me an error saying: failed to solve. please try revising dimensions or contraints

 

update 2:

 

I downloaded your file and looked at it, and you are essentially where I am now. You have your 3 stacked bodies and then you have a sketch on another plane right in the center of those bodies. I need to pull that sketch so the it is perpendicular to the bodies and out on front of them. Imagine building a box around these stacked bodies. 

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Message 6 of 15

davebYYPCU
Consultant
Consultant

It is so much easier to work with your file, parameters setup can be used, to help you understand, by seeing - better than trying to write it out.

 

If the three boards are centred on the Origin?

You make the front sketch, and the Origin is contained in the sketch, snapping the front rectangle lower mid point to the Origin creates the symmetry.

 

Sketch constraints, are powerful time savers, due to most being automatically inserted when sketching, but they only work in the active sketch.

Sounds like you are trying to make your colinear when should be parallel.  When you learn to Project body articles into current sketches, your troubles will be reduced.

 

Sure can do a screen cast, with your file data.

File > Export - Save to hard dive, and link to it in the attachments box below.

 

 

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Message 7 of 15

Anonymous
Not applicable

I'm working on the file that was uploaded by the person in this thread. Its the same principle. if you download that file you will see that there is a sketch just floating in the middle of a group a solids, but it needs to be attached to the FRONT of the solids as a border around them.

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Message 8 of 15

Anonymous
Not applicable

I will attach a file I just made that does what I want. But i had to really do some bs to get it to work -- i'm hoping there's a smarter way.

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Message 9 of 15

davebYYPCU
Consultant
Consultant

I agree, that's too hard.  I'm confused, you have no user parameters in this file.

 

I have got the screencast in processing, so will just add the link here, https://autode.sk/2GBNLrL

 

I have attached the file, constrained the sketch number one, then sweep the profile of the outside frame, cutting that frame into four pieces.

 

You need some sketch training, the frame part you placed on the origin as I suggested, but for that frame, you would align it to a plate mid point.

You need to research Components and Rule No.1 

 

Whilst I have made your frame quickly, following your data, but there are more efficient ways to construct your model. 

One plate, one long rail, one short rail, place and join copies.

 

might help, happy to answer questions...

 

 

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Message 10 of 15

Anonymous
Not applicable

thank you for the demonstration. You were using techniques i'm nowhere close to using yet I think. But to give you an idea on what I'm trying to achieve, as I dont think it was ever clear. I am including an image of a model from a pdf i've found. You will notice the same 3 layers, as well as the perimeter border around it. that's all. Maybe if you could tell me as to how you would approach that it might make more sense to me.

sample.PNG

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Message 11 of 15

davebYYPCU
Consultant
Consultant

There might be other ways, 

 

Has User parametres. 

File attached, 

 

TTop.PNG

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Message 12 of 15

Anonymous
Not applicable

Sweet, so I'm looking through your history on this file, and right from the beginning I have things I did differently, so if you dont mind to explain some of these it would help me alot, otherwise if this is now boring to you, its cool too :).

 

But after your first sketch for Board,  you extrude it symmetrically so that it extends below the plane. any reason for that?

 

Moving on to Rail - Sketch2. What is the red circle at the mid point of the rectangle? Is that your midpoint constraint?

I notice  you like using the sweep function. Is that a pretty normal function that most use and I should learn it!?

 

I'm confused on Rail - Sketch 3. I think what you're doing is making the miters, but what are you actually doing to make them? What if you just few 4 small lines, 1 in each miter corner is that going to result differently? I dont see anything that tells me what this red circle is in each inside corner though. Also, one of the lines is blue, one of them is black (on each side)

 

Then you cut the bodies from board and put them into rail

 

Then, I guess split allows you to split a body at a line or something, and you do that in the 4 corners

 

Next, are you just taking each body and creating a component from it?

 

Why do you turn everything into a component? Like each layer you make its own component

 

The grounding action at the end, what does that provide you with?

 

And lastly, the rigid group at the end, I dont see that doing anything either.

 

....

 

Then has been a tremendous help to me. I definitely learned as a veteran would approach this type of project, and it was really neat to follow it. So thank you!

 

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Message 13 of 15

Anonymous
Not applicable

I think I get it! You grounded one of the components, then just created a rigid group out of the rest of them as a fast and easy way to constrain/join them?

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Message 14 of 15

davebYYPCU
Consultant
Consultant

Ok, step by step, - is no problem, 

 

But after your first sketch for Board,  you extrude it symmetrically so that it extends below the plane. any reason for that?

Yes Sir, As much as possible you use the origin for symmetry,

you will see when the second and third layers are made, they are spaced thickness apart, and the thickness of the table is still symmetric,

 

Moving on to Rail - Sketch2. What is the red circle at the mid point of the rectangle? Is that your midpoint constraint? Yes it is Horizontally tied to the Model origin in the sketch

I notice  you like using the sweep function. Is that a pretty normal function that most use and I should learn it!?  Use the tool that does the job,

Probably only my attitude, I only draw one, and copy the rest for most of what I do, sweep gives the instant result, so that means one profile sketch, for the four pieces of timber we need later on (path sketch was already there to use.)  In real life you would cut the rails from longer stock, same thing.

 

I'm confused on Rail - Sketch 3. I think what you're doing is making the miters, but what are you actually doing to make them?

Yep, cutting the mitres, one rail becomes four pieces, I have collected the eight purple points by Sketch > Project,

Joined lines to those points, and then extended the lines, so they join inside the table space.  When you change table size, the mitres still work!

Used Split Body, select the rail, and the 90 degree line is the cutter,

Doing it this way, avoids a Fusion error, if you use one of those lines, Fusion will fail to split the body as it needs a two piece result, and cutting the first mitre like in real life doesn't work in Fusion.  Using the 90 degree cutter avoids this error, and you get four pieces from two goes with the Command. 

 

What if you just drew 4 small lines, I did,

1 in each miter corner is that going to result differently? Fusion provides an error as above for the first operation, 

 

I dont see anything that tells me what this red circle is in each inside corner though. Top corners of the rail (8 of them) were Projected to the cutter sketch - as above - needed for the parameter changing capability required

 

Also, one of the lines is blue, one of them is black (on each side)  Should all be black, but didn't chase why not, 

 

Then you cut the bodies from board and put them into rail

Nope, the table boards are in a separate component to the original rail component, after cutting the rail to four pieces, they are converted to 4 components.

 

Then, I guess split allows you to split a body at a line or something, and you do that in the 4 corners, As above yep that's it

 

Next, are you just taking each body and creating a component from it? Yes

 

Why do you turn everything into a component? Like each layer you make its own component,

 

In real life you will have 7 pieces of the table to cut, and glue

In Fusion, Joints work with Components, not bodies,

2d Drawings need Components, (I don't use them)

Bill of Materials needs Components, (I don't use them)

Components are easy to work with, in Assembly mode.

 

The grounding action at the end, what does that provide you with?  Components are free to move accidentally,

I used it to show you that the table is still locked solid to the model origin, make you aware that the command is there, and it can be used first when making the component - even if the Component is empty.  Should be used on the known base section of every Assembly model.

 

And lastly, the rigid group at the end, I dont see that doing anything either.

 

Wrong, the Rigid group is the glue - stops the rails from being able to fall off the edge of the table, Rails were free to click and drag until this is done.

 

 

Might help...

 

 

 

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Message 15 of 15

daniel_lyall
Mentor
Mentor

There's realy a lot of ways to do what you wont, you could do it with one sketch in total or 2 sketchies.

 

Two sketchies would be the easy way, one for the 3 boards and one of the border.

 

The border sketch would be one rectangles with a offset of the rectangle going in and a line sketched from the inside rectangle to the outside rectangle in each corner, then do an extrude.

 

for the boards do a project onto one inside faces of the inside of the rectangle then sketch in two line evenly spaced apart, then when you do the extrude do it as a to object what is the opposite side and set it as a new component do this for each board.

 

If it is constrained properly all you need to do to change its size is to edit the rectangle sketches length and width to change the thickness of the border the offset changes that size you can do the offset as a user parameter.

 

example attached 


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