Some timeline steps are grayed-out

[haniysf]

Greetings,

I'm facing a situation where some timeline steps are grayed out and not showing in the side browser unless I roll back history before a specific step. Also, some of these steps are movable along the timeline while others are not. what am I missing here? I ran into this as I was trying to move a cons. plane step before a sketch to be able to redefine the plane to this plane.

Cheers,

Hani

[TrippyLighting]

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@haniysf wrote:

Hi Phil,

If you'd like to know why I want to use the loft method I'll be glad to elaborate.

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It would be interesting to know, so plase do elaborate.

[haniysf]

My project is about an airplane that has 2 skins, which is a patent-pending concept of mine. (if interested, please visit my site for info about it.)
The skins meet at certain parts like the bottom of the body to become one skin, while they have a gap between them at other parts like the nose, the tail, and the top. I first used the T-spline approach and came up with a fairly close result to my goal. next, I wanted to use this body to produce the second (outer) skin by creating multiple construction planes through the body and projecting the section of the body touching these planes on them. With these projections being separate sketches, I was going to change every one of them to engulf the inner skin and create rails for a loft that will produce the outer skin. Unfortunately, it turned out that the projected sketches were uneditable, so I tried the loft approach for the inner skin hoping to get a uniform cylindrical body. this would have allowed me to produce cross-section sketches for the outer skin guided by the sections of the lofted body. Although the profiles for the loft are perfect circles, the end result was a body with semi-flattened sides. this took me back to square one.
I was hoping to get some guidance as to how to get the loft to preserve the circular form of the profiles.

Regards to all,
Hani

[haniysf]

Thanks Phil, You are a star
Really appreciated,

Hani

[PhilProcarioJr]

@haniysf

If you have profiles of the circular parts of the body all the way down the length of it there is a much more accurate way to do this.

[TrippyLighting]

Looking at your model and based on your description I believe what you are looking for can be achieved with providing the loft not only with more rails but also with more profiles.

The loft simply needs more control inputs to know where you want to start with the cylindrical shape.

In fact, I believe this can be done more easily with a T-Spline, but with the disadvantage that it is not parametric. OTOH that might not play a big role in this design.

You can snap a T-Spline to these profile circles and rails if needed. The tool for that is in the Modify->Match menue and I find it to be very powerful.

You can actually edit projected sketch elements. You have to select them, right-click and choose "break link" fom the pop-up menu. Of course, as the name suggests, in that case the connection to the original profile is lost and any changes made to the original shape will not be reflected in the projection.

I am not exactly sure why you would need those projected profiles, however.

If you want to create an off-set equidistant surface from the inner hull, you can simply use the push-pull tool. This will create geometry by off-settng from the original surface along the surface normal.

[haniysf]

Thank you, Sir,
I'll go through your suggestions and see where I reach.
BR
Hani

[haniysf]

I thought that the loft takes only 2 profiles, I'll add more profiles and make sure that the rails touch them, I hope it works as I want it to.

BR
Hani

[PhilProcarioJr]

@haniysf

You can have as many profiles as you want.