Unable to project sketch to a curved surface

[Jaeger1787]

Having searched the forum, it appears that I am like many folk in having difficulty in using the project to surface feature command.  This particular feature seems to be a bugbear in several of my drawings.  In this particular case, I have created the curved strips in sketch 'Rain strips'. When I choose 'Project to surface', I find that having inserted the parameters, the OK button is greyed out.   See picture 'Can not project to surface'.

Can not project to surface

I notice that the icon for a sketch (Roof profile) is highlighted in yellow, so I assumed that is causing the problem.

Error in sketch 'Roof profile'

But, when I examine this sketch, I still can not work out where the root cause lies.

Roof profile error??

Please advise.  I attach the file.

Thanks.

Keith

[g-andresen]

Hi,

1. the error at "roof profile" was "removed" by removing the link
2. project to surface requires a separate (new) sketch

günther

screencast

[HughesTooling]

First the project problem I notice the last sketch in the timeline contains the curves you want to project, did you create another sketch for the projected curves? You can not project curves into the sketch that contains them

Image shows I've created another sketch and with it active projection works as expected.

[HughesTooling]

Something else you should address is only one of your sketches is full constrained. You will find you get unpredictable results and inaccuracies if you leave curves unconstrained.

Only your first sketch has the red padlock showing it's fully constrained. The one at the bottom is the one I created for the projection.

[Jaeger1787]

Gentlemen.

Thank you for your advice, which as always teaches me something new, although sometimes, I still don't understand what is happening. 😟

Guenther.  Following your screencast, I was able to solve the error in the roof profile sketch.  Thanks for that.  I had more difficulty in following the construction of a new sketch to project the rain strips.  At this point, the action was a little too fast for me to keep up with. As far as I can see, you create a new sketch at 0:49, by selecting the XY plane, but do not actually sketch any elements upon that plane.  Correct?  The result is an empty sketch 16 I think.  You then project to the surface of the roof.  I do not see the purpose of creating this otherwise empty sketch but accept that it is necessary.

As it happens, I managed to obtain the desired result of modelled rainstrips on the roof by using the Push/Pull feature 'from surfact' to a given height.

Mark.  Re unconstrained sketches.  Whilst I take your point, I have examined all of the sketches, and with one exception I can not work out what else is required for them to be fully constrained.  All necessary dimensions are in place.  For example, kindly look at the Plan View sketch and tell me what I need to add for it to be fully constrained.

Regards.

Keith

[HughesTooling]

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@Jaeger1787 wrote:

Mark.  Re unconstrained sketches.  Whilst I take your point, I have examined all of the sketches, and with one exception I can not work out what else is required for them to be fully constrained.  All necessary dimensions are in place.  For example, kindly look at the Plan View sketch and tell me what I need to add for it to be fully constrained.

Regards.

Keith

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First off you need to fully constrain the construction line, in this case it's not that important as it's just the length but if it's not constrained you can't fully constrain the sketch and get the padlock. The height of the rectangles is not defined and also the position vertically. Screencast should make it clear. At the end I use a horizontal constraint, pick the origin then press shift to select the midpoint of the line.

Mark

[HughesTooling]

A bit more on project to surface. As I said above you can not project curves into the sketch that contains them! You need to create another sketch as a destination, could be the XY plane but as the projected curves end up as 3d curves in this case it doesn't really matter. The sketch does not end up empty, it contains you projected curves.

Mark

[g-andresen · Accepted solution]

Hi,

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@Jaeger1787 wrote:

As far as I can see, you create a new sketch at 0:49, by selecting the XY plane, but do not actually sketch any elements upon that plane.  Correct? 

YES 

The result is an empty sketch 16 I think.  You then project to the surface of the roof.

"NO/YES > the projection is part of sketch 16

I do not see the purpose of creating this otherwise empty sketch but accept that it is necessary.

This is not my idea. You said in your opening that you wanted to have this projection.

As it happens, I managed to obtain the desired result of modelled rainstrips on the roof by using the Push/Pull feature 'from surfact' to a given height.

This is also possible with the extrusion tool

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günther