How to control scale point for parameterized box; how to give coordinates numerically instead of clicking; how to control which coincident point is selected

[freviWX56W]

I want to make a box whose dimensions are parameters, then perform a series of operations on this box; rotate it, sketch and construct planes using its vertices, etc. I can create the parameters; create a box by drawing it, then go in and tell the boxprimitive object to use the parameters I created. However, there's a sketch left over from the drawing which doesn't change and has the useless dimensions I clicked on to initially create the primitive. Is there a better way, like a way to create a box using a text command that I can initiate using my parameters?

1. I need the starting corner of the box to always be at origin. When I change the parameters for the box dimensions, I don't know what point it scales from, and it's not origin (which is the first point I clicked on to create the box primitive). How can I control that?

2. I need to sketch lines that are tied to vertices of my box that change when the parameter values change, but also one of them happens to be at origin; when I change the parameter, the vertex moves but my sketch line still starts at origin and that wrecks the design. How can I tell the model to use the vertex (or a particular vertex) of the primitive and not any other point that happens to be coincident at current parameter values?

screen shots attached

thx

[davebYYPCU · Accepted solution]

Fusion is a sketch based modelling software.

Forget you ever had the misfortune to find and use a Box Primitive.  They are only partially parametric.

With a combination of fully defined (all black, purple or green) sketch articles and construction planes, you will get all your requirements working as expected.

1. Use a sketch on the Origin plane of your choice, and in that sketch a 2 point rectangle will attach to the Origin.  Extrude the shaded blue profile.

2. If referencing a vertex, and it is black (fully defined) project it into the sketch with the Sketch Project Tools, will be purple. (Essential for parametric changes and Loft Tool.)

Might help....

[freviWX56W]

Thanks, that is great. Is there a way to parameterize the dimensions of the initial 2-point rectangle?

[freviWX56W]

I just sketched a 1x1 rectangle, extruded it, and then moved the relevant faces using my parameters (in expressions). Seemed to work fine. All subsequent operations to create the configured model versions worked as intended.

[davebYYPCU]

Pleased for your success.

If you know the setting up and using parameters, the sketch dimensions are set to those labels, 

Start a dimension, start typing the name of your parameter - select that name from the drop down list, and set the item to that value.   

Trying to use blue sketch articles will give weird results, before that sketch is fully defined, but will work as expected in fully defined sketches.

Primitives are a relic, can be useful in insignificant (quick) demos, but should be avoided.

Might help….

[freviWX56W]

Thanks very much for introducing me to the Sketch Dimension tool.



So, to create a parameterized rectangle takes 13 steps:



1. Define parameters, e.g. length, width
2. Sketch an arbitrary rectangle, finish the sketch so it exists in the
timeline
3. Edit the sketch (right-click, select Edit Feature)

a. Choose Create|SketchDimension
b. Click on the edge you wish to set the dimension for
c. Click somewhere else to get the activated dimension field
d. Start typing the name of the parameter in the field
e. Click on the parameter name (or make sure it's highlighted then
press Enter)
f. Repeat steps a - e for the other edge of the rectangle



Crazy.



It would be nice if activated dimension fields showed up automatically when
sketching, they way they do when creating a primitive



It would also be nice if parameters created in Design mode were available in
a manufacturing model, but that's a different question.



Thanks very much for your help.

[davebYYPCU]

Crazy - but the live dimensions are there as an option.  Use Tab key to jump between live text boxes.

For a tilted rectangle

1. is presumed.

2.  Start a sketch, start a 3 point rectangle, click the origin, pull out to first point, click, pull out for outside edge position, set parameter name in the dimension text box, (it's live and waiting for you) press enter. 

Set dimension for first side, if you didn't do it during the pull out.  Dimension angle.

3. Finish sketch.

How would these 3 parameters be needed in Manufacturing?

[freviWX56W]

Thanks, this is very helpful, much appreciated.

Short answer to why parameters would be useful in manufacturing:
workholding.

Working in wood. Stock is a square profile prism; it needs to be oriented on
edge to make the cuts. To make the final piece, the square profile stock has
to be rotated 90 deg about its CL axis 4 times; there are operations that
have to happen in each orientation. To maintain registration, I machine a
square backing block that exactly fits the given stock, which has a little
1/8th in pocket at 45deg. the stock prism fits into, and the stock gets
screwed into this (and that assembly gets screwed into the spoilboard). If I
had my parameters - the exact dimensions of the stock - I could model this
backing block right in the manufacturing model. Instead, I had to make a
separate model of it which gets import-derived into the manufacturing model.
This screenshot shows the relevant pieces (there's more to it).

I guess could model the backing block in the design space, but I keep the
design space/model exclusively for the desired outcome; that seems like best
practices.

Thx