Can't Select Area Confined By Lines For Extrusion - Get Whole Surface Selected

[cmoher3]

I just bought a book and am working through first exercise. It's an Oldham Coupling, which is basically a round disk with a raised key on either side and at right angles to one another. The first side went of without a hitch. I extruded the round disk from a circle, drew two lines and with constraints made the lines coincident with circumference, equal in length, horizontal/vertical and the right key width. I then extruded it the directed key height. When I went to repeat process on the opposite side , after selecting the final step to extrude, the entire surface keeps getting selected, not just the area confined by the two lines, such that I cannot extrude only that surface, within the lines, rather the whole face. I've tried backing up and redrawing the two lines and restraining them all over again, but still have the same problem. Your help is appreciated.

[davebYYPCU]

Nothing wrong in your file, the top will select as well, the hidden projection lines have divided the profile in two,

I can only presume with all sketches turned on you are not selecting the correct profile.

Might help....

[cmoher3]

Sorry I am not understanding your reply at all. I'm trying to select the area between the two lines I've drawn but I cannot. Instead I get the entire surface. It's as though the lines are not complete and on account of a sort of 'leakage', I get the whole surface highlighted for extrusion. I do note that the 2 lines I did draw show up on the other side of the disc rather than the near side as intended. I've done these lines several times and I can't get them to show up on the side facing me, as demonstrated when I rotate the view and I certainly can't get the area inside them to exclusively get highlighted when i click between them. the whole side of the disc is flooded with the color blue.

[cmoher3]

... and I don't understand your comment "with all profiles turned on" ??

[HughesTooling]

Works fine for me. Do you have any selection filters enabled?

Mark

[jhackney1972]

As @davebYYPCU and @HughesTooling have mentioned, your model will extrude without issue as it is modeled.  If you happen to have other profiles, other sketches showing, then you can use the "left-click hold method of selecting the profile you want.  Take a look at the screencast and watch for this step.

[cmoher3]

Maybe I should have mentioned that I am an absolute Newbie. How do I check if I have any selection filters enabled ? Thanks.

[HughesTooling]

Selection filters are here check selection priority as well.

[cmoher3]

Thanks. By some inexplicable reason I am able to select it now although I don't recall doing anything different this time. I still have a problem though: Those two new lines were supposed to be on the face opposite the key already on one of the faces. So, if this was a coin, I am trying to put an extruded key on the Heads as well as Tails side opposite and at a right angle to the each other. The end result as you have illustrated is correct in the orientation of the two keys but they should not be on the same side of the round disk as each other. I don't understand, after flipping the disk around and drawing two new lines, why they did not end up drawn on the face that I had showing, rather on the opposite side of the disc.

[cmoher3]

OK I have a better understanding of the problem now. The fact that my drawn lines are ending up on the opposite side of the disc than what I intended is the problem. I drew this disk, extruded it, drew 2 lines extruding them to get my first raised key. I then flipped the disc around and drew another 2 lines to put a key on the opposite face. MY LINES HOWEVER DID NOT END UP ON THE CORRECT SIDE FACING ME, THEY WENT ON THE OLD OPPOSITE SIDE !! Why, I do not understand.

[jhackney1972]

The next time you sketch on the wrong plane, try the "Redefine Sketch Plane" function.  You right-click on the sketch, either in the browser or the timeline to see the function.  Then it is a simple matter of selecting the correct sketch plane.  Also can use the "Start" option in the Extrude command.  Take a look at the screencast for a better understanding.

Screencast will be displayed here after you click Post.

784cd52c-b20c-437f-86f9-0fa429b3d786

[jhackney1972]

Screencast did not attach

Screencast will be displayed here after you click Post.

784cd52c-b20c-437f-86f9-0fa429b3d786

Click here for video if you do not see it.

[davebYYPCU]

Ok, all your sketches are on the same plane / face of the disc.

You will learn quickly, to declutter the window with lightbulbs turned on or off for the task at hand.  Without mentioning Select Other.

Your flooded all blue Extrude profile, comes from you clicking on the other side of the sketch plane, in effect the disc sketch is the closest to the back face, so with the disc sketch visible it is the first one Fusion sees. Or you are clicking on the back face of the disc, which is a legitimate choice to Extrude without a sketch.  

In my first reply I did not know you were going to the rear, but I demonstrate that the 3rd sketch was divided by Fusion, cause of the way you constructed the 3rd sketch.  It is expected behaviour so my comment was that there was nothing wrong in the file.  I selected sketch 3 profiles from the front, so they were on top - hope that makes sense now.

That means to do what you intend, Hide your body and sketch 1 and 2, lights off, then only sketch 3 can be utilised.  You still have to select the 2 profiles in the centre of the sketch, start pulling the Extrude and unhide the body, set distance and Join.

Select Other - when you left click and hold, shortly thereafter you receive a menu listing everything under the mouse pointer, highlighting your correct profile is done by hovering over the menu item to highlight it in the window, and selecting the right one, twice in your case.

Might help....

[cmoher3]

OK I'll give it a go but find this to be very strange. If I wanted to draw those lines on that side of my disc, I would obviously not have flipped it around to draw on the opposite side, but left it oriented in it's original way. The logic behind this fails me. Imagine a word processor that allows users to flip the writing surface around like turning a page, but then proceeds to write any newly entered text back on the first side. Nuts.

[jhackney1972]

Your logic sort-of holds water until your body has many faces at all different angles.  Then you want to place a sketch for a feature on one of the angled faces.  I hope now you realize why placing the sketch on specific surfaces is a great and logical idea.

[davebYYPCU]

Easy, when you created Sketch 3, it asked for a plane /  face to place it on, you haven’t got it on the back face, you may remember why that didn’t happen.

[cmoher3]

I guess I'm struggling with the concept of "sketches" then. I intuitively regard the entire drawing as the sketch but take it that Autodesk has decided each component or feature of the whole is a sketch. I think I have a lot of things to get used to that I don't find intuitive. Anyhow, I did indeed get it to extrude on both sides but unfortunately both extrusions are parallel and not perpendicular and an hour spent trying to use the constraints to force them to rotate 90 degrees has gone nowhere. 

[cmoher3]

"it asked for a plane /  face to place it on," .... I must have missed the time it asked me. I don't recall being asked anything. Just flipping it over and intuitively, like paper and pen, expecting the lines to be laid down on the surface facing me. At least that's the way my brain works.

[davebYYPCU]

If you have a pair of extrusions that are not perpendicular to each other, then now you may have selected the other sketch profile (sketch 2) , or in other words the same sketch was extruded on both sides.

John's video has shown the various ways to produce the last extrusion.  If you use the lightbulbs, you can hide the body and you will find that with all sketches turned on, looks like this,  (check the lightbulbs in the pics,)

and turning sketch 1 and 2 off, leaves you this, 

As in my earlier post, you start the extrusion with the window like this, pull the profiles to the left, and turn the body back on, will look like this

then change the cut to Join, and set the distance, before the OK.

As to how the Sketch 3 was created without being asked, that can happen too,

if a plane or profile was preselected, the sketch will be placed on to that selection,

as always most software has many ways to do the same thing....

Let us know if your stuck.

Might help....

[cmoher3]

In the absence of any other text, I went out and bought one from Amazon. This coupling is the first project. Nowhere in it, thus far, is there any mention of light bulbs nor is the concept of sketches covered at all. I guess my BIG problem is that I need to learn this program but had no counsel on where or how to start. I wish this program came with a standard text or better yet that one of my neighbourhood schools had a course I could take in it.