Projecting a sketch to a curved surface

[Jaeger1787]

I have read several of the posts on this topic and played and replayed Jeff Strater's pseudo-embossed video, but I still can not achieve the desired result on my own drawing.

Illustration 1 shows a carriage door.  I need to create the small gap that would be found between the door and the carriage frame. 

Because the lower part of the carriage has a tumblehome curve, firstly, I created an offset plane laid on the flat upper area of the carriage.  I then drew the door outline, offsetting it by 0.2mm for the gap and selected the area thus created.  I then made an extruded cut to a depth of 0.2mm, but it was apparent that the cut did not extend all way round the door.  This can be seen in illustration 2.

If I increased the cut depth, I was able to make an extruded cut all round the door as shown in illustration 3.

However, I simply could not make a projection of the door gap, because try as I might I could simply not select the gap between the two rectangles when in the projection mode.  Either one of the rectangles could be picked, but not the area between them.

Why is this, how do I work around it?

Keith

[davebYYPCU]

Extrude from Object.

you have your clearance sketch, select the groove in the current sketch, start the extrude from the face of the body.

Another way is to split face with the rectangles and Press Pull.

Might help....

[Jaeger1787]

Further to the above, I wondered if because I had laid the new offset plane as close to the surface that I wanted to project to, that was somehow preventing the projection taking place.  Therefore I increased the distance of the offset plane so it was some 4mm above the surface of the model.  It then became apparent that the sketch of the door outline was not actually on the offset plane, but was on the model surface.  See illustration 4.

My query then alters to 'How does one create a sketch on an offset plane, instead of any underlying surface?'

Keith

[jeff_strater]

that original video was made before "From Object" Extrude was available.  The example you show in the images should be pretty easy to get to work.  If you share the model here, we can take a look at the design itself.  One thing to be aware of:  Either of these methods (the "project curve to surface/offset faces" and the "extrude from object") are not a "wrapping" function.  Extrude is definitely a projection along the sketch normal vector, while project to surface has two modes ("closest point" and "along vector"), where "along vector" will give the same results as extrude.  Closest point is only marginally useful, in my experience.  But, in your case, the curvature seems so slight, that the distortion might be OK.

[davebYYPCU]

Sketch on the offset plane, to do that it must exist, you seem to have sketched on the face of the body, that's a normal workflow too.  hide the body with it's eyeball and you will see the offset plane, until selected.

Might help....

[Jaeger1787 · Accepted solution]

Good morning, folks.

Well, I seem to have achieved the result (appearance) that I wanted, but I am not sure how.  The Push/Pull function did the job, with a bit of playing around after I redrew the door outline on the offset plane.  The only problem I can see is that the depth of cut varies as it is not a constant from the body surface, but from the offset plane.

I find the semantic differential between our two languages sometimes does not help.  It may be that I was mistakenly thinking that the projection tool would apply a sketch to a curved surface, following that curve, so that an extrusion to a set depth would apply all round the curve evenly, without variation.

Thanks for the suggestions.  As there is rather a lot of material to be etched into or laid on the surface of the carriage, I will be using this technique considerably for a while unless I can find a better one.

Keith

[davebYYPCU]

If not sure (varying depth?) and having lots to repeat,

attach the file, for an exact explanation using your data.

[jeff_strater]

the depth problem is from not selecting the "from object" as the type, if you are using Extrude.  Share your model, please, and we can explain it in a quick screencast

[Jaeger1787]

Hi Folks.

The next job to do on the carriage is to recess the panels shown in blue on the attached image.  These are to be recessed by 0.2mm.  Because of the curve of the tumblehome in the lower part of the panels, a flat panel surface would not be suitable.  Hence, the depth  needs to be constant.

Following recessing of the panels, the 'planking' lines need to be cut, again by 0.2mm.  Most of these, in the flat area of the side should be relatively straightforward, as I have modelled planking on a number of vehicles previously, albeit without a tumble home.

I appreciate your offer of making a screencast, Jeff.  I attache the file as requested.  Might I make a plea though.  Having watched several screencasts in trying to resolve problems, I find that many of them are too fast, with the cursor flying about like a demented bee.  Can you kindly pause for a moment whilst my eye catches up with the cursor, before you click on a command/menu/etc.

Many thanks.

Keith

[jeff_strater]

thanks for the model, @Jaeger1787 - always helps to have the data involved.  I created a screencast (with rare audio commentary, since I hate hearing my own voice) that I hope minimizes the "demented bee" factor (love that description, I know just what you mean...).  I had hoped that "From Object" would be the solution, but I learned/remembered that you are limited to what you can select in From Object to one face, and we need two here.  The solution, then, is to use a bit more complex approach - Split Faces + Offset Faces to do a "pseudo emboss" operation (side note, we are even now working on a true Emboss feature which will make all this much easier in the future).  There may be other ways to do this, but this is the one that I know works:

screencast:  https://knowledge.autodesk.com/community/screencast/c81c8663-4012-414e-ae32-f4c03b871594

[jeff_strater]

embedded screencast:

[Jaeger1787]

I am sorry, Jeff, but I can not get my head around this.  Part of the problem is that if I enlarge the video to full screen, the lower part below the navigation tools disappears.  I can not stop/start, rewind or slow down the player as a consequence.  Before I enlarged the screen, I did slow down to half speed, but could still not follow the actions.

It appears that some dialogue boxes open, then are closed without any action/result occurring.

It looks as  though you modified the door outline extruded cut, but I can not follow your actions and do the same with the recessed panels.  I also find that when I try to select the work face, often, Fusion simply will not let me do so.

What I need is a Fusion for Dummies approach with numbered steps and clear screenshots of each step and the resultant action. 

Thanks for trying to guide me.

Keith

[davebYYPCU]

Sorry Jeff there was no sound, and I will stick to the Extrude to / from object for simplicity to explain.

@Jaeger1787 Edit Sketch 57, project the curved face edge into the sketch.  Highlighted and is purple in the pic.

You profile is bisected with this line.  2 Extrudes, result - perfect.

Cut Extrude from Object, select lower u shape groove profile, select from curved face, set depth 1.6mm.

Cut Extrude to Object, Select top u shaped profile, rotate model so you can find the corner point of the first groove, select the point. (Bonus - change depth in first Extrude, this one adjusts as well)

For the other parts that cross the curved boundary do the same,

What shape is the board groove?  Square - vee, filleted

Can you send back the file with a profile of the board?  Can show you how to speed things up.

My file attached.

Blue lines should keep you awake at night.

Might help...

[jeff_strater]

sorry, I recently upgraded to Mac Catalina, which has ridiculous levels of security, including blocking the microphone, and I cannot find a way to turn it back on again.  Basically, I am recommending using Split Faces and Offset Faces to do this cut:

and again using the inner rectangle:

this produces a small face with the window outline:

select those faces and use Offset Faces, type in -1:

that will produce the cut that I think you need

[davebYYPCU]

Yeah, 6 of one half dozen of the other, 

His next steps are the same, recess panel then board separations.

[Jaeger1787]

Thanks Guys.  Particularly Jeff and daveb.  I really appreciate the efforts you are all making to guide me with this task.  I have printed out the recent messages and illustrations to paper so that I do not need to keep switching from one screen to another whilst I work out the moves to make.  I can now study this and determine what I need to do.

I shall let  you know how I get on in due course.  Just don't hold your breath in the meantime.

I will study the .f3d file you sent me as well Dave.

To answer your question re the boards, normally, these would be tongue and groove boarding.  However in the scale I am working at (1:32) all I require is a representation of the joint to create the planking appearance as seen in this view of an end panel attached.

Regards.

Keith

[davebYYPCU]

Dang, I nearly did them as a vee cut, (for two chamfers)  but as you can see the boards in the pic were from this sketch as square grooves.  

This detail is almost too small.  Are you using a Filament or resin printer?

[Jaeger1787]

davebYYPCU. 

To answer your  question, I am using a filament printer, currently with 0.4mm nozzle, 0.2mm layer height, PLA (cheap, generally reliable, fairly strong).  I have made V cuts on other models, but not lately, as a simple square slot does the job of representing the joint satisfactorily.

To return to the basic problem I have of making the projected cut.  I tried following your advice, but difficulties start immediately.  The surface has two areas - one is flat, t'other is curved.   I simply can not select one part only of the surface (see picture).

Second problem is terminology.  In the Extrude dialogue box, one has to select a Profile, a Start position, possibly an Object.  Fusion defines a Profile as the Assets, Drawings and Projects I have created.  (Note there is even a different meaning to the word 'Project' from the context we are using it here. 

The dialogue box requests an Object to be selected.  But, what is the Object?   My object is to create a recessed panel.  But what do I select to do that?  You see what I mean by semantic differential?

Keith.

PS.  How do I embed a picture into the text above instead of  attaching it as a stand-alone file?

[davebYYPCU]

Pictures in messages - this Forum has a Tool bar similar to Fusion.  The camera icon, takes you to a select window, click select files, will take you to a hard drive directory, select the picture file from hard drive, and when it’s ready you can press Done.

The picture will be put where you left the cursor.

Yes making a model is a Project, Files - data panel stuff.

Project in the sketch area, is a menu item, has five tools.

Referring to message 13 above, 

We need to use Create > Project > Project, this dialogue has two options, body and article icons, select or keep the articles icon active.  Click on the black face line in your picture.

Back soon with a screencast.

[davebYYPCU · Accepted solution]

Sent Screencast link in PM, cause it is too long for forum guys, and the sound is not so great.

Might help....