planes, midpoints, origins and why

[chad38]

Hi. I'm just curious....what is the point of the auto-resize of the origin planes if you cannot dimension or constrain to them anyways? Or am I missing something? Is it possible to dim or constrain to the center point origin or to a midpoint on existing geometry? I've always found that in dimension driven solid modeling it's important to fully define your features, and I'm wondering why it seems to be going out of it's way to not let me do so in a simple way without adding a bunch of extra steps to the process unnecessarily.

I could be missing something here, but it's not possible to run a dimension off a plane, midpoint or the origin, correct?

[blair]

Project the plane onto the sketch with the project geometry tool. This will allow you to dim to it in the sketch. In the model enviro you can constrain to work plains with constraints and joints. Since a work plane projects to infinity
It has no mid point.
The same with the origin pint in sketch mode, if you project the point to the sketch you can dim to it.

[Cadmanto]

What Blair said is true.  You ahve to project geometry using the planes if they are to be useful in your sketches.  A lot of times I will convert the projected geometry off of the plane to a center line.  Very useful when revolving or creating diameter dimensions.

As far as the auto size, that is most useful especially as your model grows or shrinks.  Don't want really tiny planes or gigantic planes in extreme cases. 

If this solved your issue please mark this posting "Accept as Solution".

Or if you like something that was said and it was helpful, Kudos are appreciated. Thanks!!!! 

     

[_DanSolo_]

this one has always bugged me, not sure why the need to project it onto a sketch, as the plane is still there fixed in space. seems like extra steps to achieve a basic task.

[johnsonshiue]

Hi! It is a design choice made by Inventor team. As every decision, there are always pros and cons. For this particular behavior, I believe it was made for consistency, clarity, and performance purpose.

Basically, all objects in a 2D Sketch should be on the sketch plane. Only 2D Sketch entities can reside in the sketch. Otherwise, it would be hard to tell the relationship and reference. Also, the projected geometry can help stablize the sketch. Assuming the project source geometry disappears or fails to compute, the projected sketch will still survive and the feature consuming the sketch can still be computed.

Certainly counter arguement can be made here. But, this is a design choice. If you have any idea possibily fulfilling above requirement without the need to project geometry, please feel free to share it here or Ideastation or send it to me directly (johnson.shiue@autodesk.com).

Many thanks!

[Cnoj]

We have an 'Autoproject origin on sketch create' option so I see no reason not to have 'Autoproject origin planes..' also. I do this manually on almost every sketch.

[wimann]

If you origin point is autoprojected on sketch creation then I can't imagine ever needing the origin planes for dims/constraints. The origin planes resize so that they are more easily utilized in an assembly. Plus that is optional. You could edit your template and turn the auto-resize off. 

So I guess your issue is that you don't see a purpose for the origin planes if they cannot be dimensioned to in a sketch without first having to project the plane into the sketch. I guess I get your point but this has never been an issue for me. I usually leave my origin planes invisible anyway.

Edges can be set to autoproject on selection. In other words, if I initiate the dimension command, I can select an unprojected model edge and a line (or whatever second entity) and it will project the model edge without me telling it to. This does not, however, work for planes and I do agree that it could and would probably be an improvement.

I will say that not being able to dimension directly to the midpoint of a line is moderately inconvenient. But it can be constrained to. And with the drop of a sketch point, it can be dimensioned to. I'd say there's a point to that comment. Dimensioning to midpoints ought to be added (if it hasn't already... I'm not in 2015 yet).

When I read your post, it seems to me that the issue is that you want to be able to dimension to planes and points without having to project them first. Am I right?

[_DanSolo_]

When I read your post, it seems to me that the issue is that you want to be able to dimension to planes and points without having to project them first. Am I right?

Exactly! Planes are good for this because they are true datum planes, infinite in their respective plane. So the need to project them is really a redundant step as the referenced datum point in the sketch naturally projects itself into the sketch simply by intersection. The plane is infinite in 3d space.

Really by making one have to project it. The software is just adding an additional task that should not be necessary, and in other software is not required to do.

Again I recognize this is a choice Autodesk has made. But if they want to make things quickly and more simple. Just treat the planes as present in the model space and allow for complete utilization without having to project them.

[wimann]

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@_DanSolo_ wrote:

...allow for complete utilization without having to project them...

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Yeah. I would pose no argument there. I still probably wouldn't use them lol. I'm mainly on board because it would have very little effect on my work flow. I primarily use the origin point and will on rare occasions project in user work planes as needed. They, as a projected line, often cloud my sketches with unnecessary noise. So I work around them with either parametric relationships or project points (not planes). You could say I avoid it to keep my sketches simple and clean. With that said, being able to use them without making my sketches messy (projecting) could prove beneficial.

[_DanSolo_]

In 2d sketches the planes can also enable you to have firm dimensions that will not change as the part or sketch changes. in other words you  constraints are not dependent to the next feature. If set up corectly you can more easily ensure your model or assembly will not have errors if a part is modified.

Planes are also usefull to establish points in 3d sketches, and for constraining components. For example if you want to ensure different parts are constrained on the same plane without being dependent on geometric features on other parts that may change.

Once you utilise them to their full potential, you will not want to work without them.

[JDMather]

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@_DanSolo_ wrote:
 

Once you utilise them to their full potential, you will not want to work without them.

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I never project planes into sketches.  I think I am making pretty good use of their potential.

[_DanSolo_]

I not sure if you would know. Have you used them in any other software? If the functionality was corrected you would likely find them to be a time savers and less headaches with sketch constraints.

[JDMather]

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@_DanSolo_ wrote:

I not sure if you would know. Have you used them in any other software? If the functionality was corrected you would likely find them to be a time savers and less headaches with sketch constraints.

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I don't have any headaches with any of the CAD programs I use.

I already stated - I think I am using the full potential of workplanes pretty efficiently.

As far as saving time - I am pretty fast.  At least I think so.
I should have mentioned - I am lazy and avoid work that I don't have to do.

[_DanSolo_]

what software are you using besides inventor?

[JDMather]

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@_DanSolo_ wrote:

what software are you using besides inventor?

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AutoCAD
SolidWorks

Creo