Help with workflow to create features on BRep bodies

[nkloski]

Hi....I am modeling a small children's bike.  The general shape of the bike is easy to model, but as I am copying something in the real world, I also desire to copy some of the decorative designs on the outside.  For simplicity sake, let's say these are the "ribs" of a radiator.  Here is my workflow:

-create the body in Sculpt

-Create an offset plane

-Start then stop sketch on that plane for the ribbed features 

-Create a blank sketch on that same plane

-Use the Sketch -> project to surface command to select BRep body, and then sketch curves to project to

-Go into patch environment to create patch from projected curves

-Thicken patch into a new body.

Now here is what I don't get...this small ribbed feature creates:

-1 construction plane

-2 sketches

-2 bodies 

...and that is per feature I want to make!  Think about creating 20 separate features, that would be 100 "items" to track in the browser....is this the right way to create decorative features on the sides of nonplanar BRep bodies?

Thanks!

[innovatenate]

Thanks for posting your question. I've made a screencast below that I think accomplishes a similar result with 3 features in the timeline.

An additional Tip that maybe helpful is how to create a DXF file from a sketch so that you can utilize this in a CNC router/laser/waterjet/etc...

I hope that helps! Let me know if you have any questions or concerns.

Thanks,

Nathan Chandler

Autodesk, Inc.

[nkloski]

Thanks, Nathan, for the assistance!  Here is a better description (a picture = 1000 words, etc.)

I have essentially modeled the body of the bike in a nice and smooth shape, and now desire to add on these decorative flares on the outside.  Less than being entire features, it would be more along the lines (no pun intended) of sketching out the features I need, projecting them onto the surface, patching them, and thickening them.  Does that explain it better?

Thanks!

Nick

[innovatenate]

Nick,

Thanks for posting that picture. I can see that I was way off the mark! Rather than projecting to the surface, patching and thickening (3 steps), try creating one sketch and then using either the split body or split face command to split up the face. From there you can use the Press/Pull tool to thicken or thin out a section of the smooth bike body. If you do use the split body, you can always use the combine command at the end to join the bodies back together. I made another video below to show my work.

Let me know if this way seems any easier.

Thanks,

[nkloski]

If I could ask a follow-on question that arose from your video?

What you said works great...except that the Push/Pull command gives me an uneven extrusion when the split body curves around a curved body.

Here is a simple way of illustrating what I am saying:

-create a T-spline Sphere

-create an offset plane

-sketch on that plane

-use the split body command as you suggested

-push/pull outwards

-measure

-get different measurements

Here are some pictures:

Sphere with a random sketch "split faced" onto it:

I push/pulled it to a distance of 35mm.  Now when I measure one part, it indeed does say 35mm:

 But measuring in some places shows 39mm:

Is there a way to get a constant height all the way around that extrusion?

Thanks!

[innovatenate · Accepted solution]

On Step 3, try using the Split Face command instead of Split Body. This will enable the push/pull - offset to go in a normal direction from the sphere's surface. This will produce uniform offset results. The reason you are seeing a difference is that the split body result, offset along the normal axis of the sketch plane (that the originating sketch was defined on). 

See the below image for clarification.

instead of alon

Let me know if that helps or if you have other questions.

Thanks,

[nkloski]

Awesome as always, thanks!!!

[nkloski]

Oops...one more followup question:

The split face/body carves all the way through to the other side...what if I want to make that change only on one side of the receiving body?

The "project" workflow I stated before only affects one side of the body, the "split" affects all the way through.