help understanding project to surface

[laughingcreek]

I've been trying to use project to surface in a project, and have been getting unpredictable results.  I've made a design where I change the shape of one spline in multiple different ways to see the effect on the projected line.

I also noticed that the behavior was sometimes different when project the edge fro a coil vs a spline in a similar shape.

I thought I'd be smart and put a description of each result in the comments, but I can't figure out how to make the comments travel with design.  Apparently you can't even select the text in the comments to paste else ware,  so I'll retype here.

every thing is separated into components.

Helix from coil - this is the coil whose edge is projected onto a surface of the below components

Helix from spline - this is a spline whose edge is projected onto a surface of the below components

body 1 - the base body used in all following component.  in each case only the spline drawn between the edges of the 2 circles is changed.

sketch 3 of the following compoents has an edge from the coil proected on to the surface

sketch 4 of the following components has the spline projected

body2 - why don't the proected lines go all the way across?

body 3 - elongated spline handle of bootom control point. why are projected lines shorter?

body 4 - tangent handles puled so spline is oncaved

body 5 - elongated lower tangent handle from body 4

body 6 - made spline convex

body 7 - made very concaved.  the projection from the spline is longer than the projection from the coil edge.

body 8 - added spline fit point to straight spline of body 2

body 9 - elongated the tangent handle of new spline fit point.  both projections are shorter.

body 10 - used new fit point to make spline S shaped (same handle length as body 8).  both projections are shorter, but projections are in different places.  Why?

(I realize now that naming the components "Body #" is confusing.  It's late, just roll with it.)

Can anybody help me understand what is going on.  would like to be able to use project to surface in a predictable way.

[laughingcreek]

Just giving this a bump.  Does anyone have any thoughts?

[laughingcreek]

and because this is bugging me, I did another study design using a straight line instead of a spline for the revolve.  In this case both the helix and the spline projected the same, but there where still issues.  components case 1 - case 3 behave as expected.  Starting with case 4, the projected line starts messing up.

Is this a bug, or something I don't understand about using project to surface?

[laughingcreek]

@TrippyLighting or @cekuhnen - could you please take a look at this and let me know if there is something I don't understand about "project to surface", or if this is a bug.

[cekuhnen]

@laughingcreek

so I understand this right you want a helix on the cone surface?

[laughingcreek]

Sort of. These 2 designs are an attempt to understand some odd behaviour I was experiencing in a model I was working on. Sometimes the project would work as expected, other times the project was incomplete. I would tweak the surface, and the project would still be incomplete, but in a different place. And I was getting different results form projecting from an edge of the coil, vs the spline. Start with the fist design I posted. Click through each component and you can see the different results in the project.

[SaeedHamza]

Hi,

are you trying to create a helix path along a cone surface like @cekuhnen mentioned above?

I mean is the path what you are trying to achieve?

Regards

Saeed

[cekuhnen]

@laughingcreek

do you specify the vector correctly at project type

?

[laughingcreek]

Ok, I understand what's going on in the second design I posted now (project to surface study 2 v1).

But the first one is still confusing me.  That one is using a spline for the revolve.

@cekuhnen - I'm actually using "closest point" for the project type.  Along vector projects loops onto the face, but the closest point option projects around the face like I would like it to.

Attach is screen cast 1 of 2.  Hopefully these will further clarify

This first screen cast has two examples - case 1 and case 2

case 1 - edge from coil is projected onto revolve face.  the face was created with a straight line.  The result is what I would expect. looks good

case 2 - the line from the profile in case 1 is replaced with a spline.  the spline is straight, and the resulting revolve LOOKS identical.  The project to face command gives and error, and would like me to be "sensible" 🙂  I don't under stand why this set up fails.

[laughingcreek]

Here is a second screen case.  This one just has one example.  A straight revolve again, using a spline for the one side.  The project works, but only 2 turns are projected, instead of all of them. (I tried this one with a plain line also, and the projection for that case was again complete and as i would expect it to work.  Didn't record that part)

So why didn't it project the entire edge?

[laughingcreek]

attached are the designs resulting from the above screen casts

[saito.kh]

Hi @laughingcreek,

Thanks for sharing your designs and the Screencasts!

I tested and saw how it occurred on my machine. I have logged reports [FUS-33834, 33835] with our development to investigate these issues.

I will circle back here once I have something to share.

Thanks!

[laughingcreek]

Thanks!

[laughingcreek]

Has there been any movement on this issue?

[SaeedHamza]

Hi,

I asked about 2 weeks ago if you're trying to get a spiral path along a cone ( like @cekuhnen mentioned above ), is this the case or am I misunderstanding the issue?

Regards

[laughingcreek]

Answer is the same as the one I gave before, see the previous screen casts and attached files.

It's not a cone shape I want to project to.  It's a surface that was created by revolving a spline.  The screen casts and models in this thread has been my attempt to understand and isolate the behavior that was occurring on a part I was working on. 

Attached is another file that I'll use to try and clarify.

The design has 3 basic things in it-

-A coil whose edge I want to project

-a cylinder created by revolving a profile with all lines.

-a cylinder which the exact same dimensions as the first one, but created by revolving a profile with a spline laid out to be a straight line.

In the case of the first cylinder, the project to surface works as expected.  great

in the case of the second cylinder there is only a partial projection.  no errors or other indication as to why.  and as far as I can tell the 2 cylinders are functionally identical.

additionally, if you edit the coil to have 7 turns instead of 5, the project to surface on the second cylinder fails entirely.

[SaeedHamza]

I see, it's strange in fact, even when I modified the spline, it produced the same issue when projecting the coil

But anyway, there are other ways to get the coil path on the cylinder.

Is there a model that is as the spline case and you want a coil path on or is this thread just to know the difference?

[saito.kh]

Hi @laughingcreek,

I am sorry for the late reply.

Your issues have been logged as a bug for our development team to review - the ticket ID: FUS-33834, 33835 (for your reference).

Both of them are related to projecting curve on free-form surface, and it is very hard to project a curve on a free-form surface at this point.

Unfortunately there could not be workaround for it right now. Our developers will try to take up this issue with other team internally.

I apologize for the inconvenience.

@cekuhnen and @SaeedHamza,

Thank you all for sharing your thoughts in this thread!