Hi everybody, and thanks for your experiments.

Like I said in the french section, I try the demo with a "simple" shape, but not easy in the reality.
I don't understand how to arrive to a smooth shape. I tried different methods, but not great in the render.

I have created a new scene with clean shapes (in the attachments), and a fast test in cinema 4d to see the form which i like to arrive :




Thanks.

Hi Buzhug,

> I tried different methods, but not great in the render.

Could you post some of your results so I can see what you have tried and make some suggestions?

Did you see the sequence that I recommend in this post:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3137.5

That shows the steps that I would recommend for making this kind of shape, it involves drawing 4 curves, then doing 2 sweeps, some trimming and then a fillet to produce a rounded edge, there are screenshots in that post to help you follow along.

There's also an example model attached there named RoundedSlab.3dm

Do you have problems following those steps or is the final result not suitable for some reason? If you don't like that result can you please let me know what is not good about it and then I can try to explain how to make some adjustments to it.

One of the main things with this kind of a shape is to try and break it down into a couple of more simple broader surfaces and then build those with some more simple curves, then combine the results by filleting. That's instead of trying to build the whole thing all in just one single surfacing operation.

- Michael

The problem is how to "past" at the original curves with the fillet and the "join" of upper surface?

Hi Pilou,

> The problem is how to "past" at the original curves with the
> fillet and the "join" of upper surface?

I'm sorry, I don't understand - "past" what?

Did you see the model I posted previously? It has an angle in it like you were asking:



Also note there that the Fillet radius I used was pretty large, so that the fillet went a fair distance down the sides.

So for the fillets in my example model were actually this piece here:



- Michael

<Past = fit, follow
red + blue lines must follow the original curves lines sections

what must be in general the lenght of the "?" (in proportion)
and the angle of the end of red lines ?

Or blue lines must stop must just at the vertical of the internal bottom point? (image 2)

Hi Pilou, I'm sorry I'm still not very clear on what you mean.

But you seem to refer to the area where the fillet is going to be placed?

You should not attempt to draw that area directly - instead let the fillet be calculated to fill in that spot so that it can be automatically be created as a smoothly connecting piece.

You can adjust the shaping of the fillet by a couple of things - adjust the radius to be either larger or smaller as desired, and also with the Shape: G2 Blend option in Fillet which then gives you a "Bulge" slider that you can also adjust to tweak the fillet's shaping.

You seem to keep on trying to build a smooth piece without making a fillet, that will be a lot more difficult - the easiest way is to let a fillet be calculated to create a blending area between the 2 surfaces.

If you open up my example model, you will see that there are just 4 curves that define everything, 2 for the top surface and 2 for the side surface.

If you want to adjust the shape of the result, just edit those 4 curves to adjust things as you want.

Maybe if you can explain a bit more about how my example is not right for you it may help me to understand, right now I don't really understand why that does not work for you properly.

- Michael

Hi Pilou,

> Or blue lines must stop must just at the vertical of the internal bottom point?

If I understand correctly, you want the blue lines and the red lines to intersect near the midpoint of where the fillet will be going.

You make that portion come to a sharp edge between the 2 surfaces, don't attempt to draw each piece already perfectly round and meeting smoothly in that spot, make it come to a sharp intersection point and then use Fillet to smooth out the sharp edge.

It does not matter exactly how far the 2 pieces overlap past one another, just make them go some small distance past each other so that they fully intersect and can trim each other.

Just look at the previous file I posted for an example...

- Michael

I progress slowly but I progress :)
I must find the "Fiat lux" ;)

I study your examples but not yet find how "fit" the blue line section , i must continue :)


Something curious at this step after the sweep of the crossing lines

I have always "the crossing lines" on the surface! you have not them!

Hi Pilou, sorry but again I'm not sure if I understand - what do you mean by "fit the blue line section" ?

Are you trying to adjust the shape? If so you do that by editing one or all of the 4 curves that were used to create the model, then do the same steps (sweep + trim + fillet).

Can you possibly post a 3DM file with your blue curve in it? That would probably help me to understand. It is hard for me to follow what you mean by the blue curve when I cannot examine the blue curve in an actual model file over here.


Maybe the attached 3DM file will help - here I have removed the surface and just have the 4 curves, and also I moved the curves for the top sweep down so that they are in the place where the cap will go at the end (previously I did the sweep higher up and then dragged the surface downwards afterwards).


So the 4 curves involved are like this:



And if I understand what you want to modify, you will want to edit these 2 curves, here seen in the Front view:




Now say you want the shape to instead be more like this blue curve that I have just drawn in here:



To get that, you will need to edit those 2 curves to have each follow a portion of that blue curve. But not the whole curve, they must cross at an area where there will instead be a fillet filled in.

So pick an area that will be used for the fillet, normally this would probably be a spot that has the tightest bend in it, so for example something like here:



Now edit or redraw the curves to be shaped like this instead:




Does that help explain it any?

Try to examine your shape and see if there is a major areas that can be defined by shorter curves to sweep - those will become the different pieces, and then you combine the pieces with a fillet to produce the smooth linkage between them.


If you are having problems, please post a model file though, that is much easier for me to examine than only screenshots...

- Michael

Hi Pilou,

> I have always "the crossing lines" on the surface! you have not them!

I just happened to do the sweep in a space above the other curves and then dragged the sweep surface downwards after it was created.

Does that explain what you are asking about here?

If not, I'm sorry but again I am having difficulty understanding and I will need some additional explanation.

- Michael

Hi Pilou, here is a variation from editing the curves as another example...

Possibly you might switch from Sweep to Network with some more guide curves if you want to more finely control the top surface.

- Michael

Hi Pilou, here's another variation where I used Rail revolve to build the top piece instead of sweep.




That may make for a somewhat more even height where the pieces intersect:



But you can see it's the same basic strategy - a couple of primary sheets are modeled, they are intersected and then filleted.

- Michael

Or if you want more uniform, this is just a totally flat top, so just a sweep around the sides followed by Construct/Planar to fill in the top and bottom planes:



- Michael

Here the file ;)
Blue = original
I don't put the "base" at the middle as you, does make difference for the sweep?

Hi Pilou - your top sweep surface is different because the curves you have there are made up of 2 segments joined together. Mine makes a single surface because each curve is only made up of one segment instead of 2 joined pieces.

Try deleting the middle point where your segments touch each other to fuse them into one segment which will then make one surface for the final result.

To see the difference more clearly, run Edit/Separate on your curves, and run Edit/Separate on the curves in my example - notice how yours breaks down into 2 pieces, while running Separate on mine does not make any separate pieces?

- Michael

Yes it's that I made it by Mirror ;)
Yes yours don't make separated pieces! That's magic!

So must be one curve ( the trick I missed) and draw it by helpline for have the oposite mirror points?
Or mirror it and redraw over them?
(ah separate, select points, join, kill works :)

Hi Pilou,

> and draw it by helpline for have the oposite mirror points?

This was how I drew my version, by dragging out construction lines from the centerline so that I had end point snaps on either side of it.

But yes doing a mirror + join + delete control point where the segments touch will also work.

In the future I want to add a "symmetry draw" function to make it easier to draw single segment curves like this with only needing to draw the points on one half.

- Michael

Symmetry Draw I LOVE IT!!! :-D

-Will

Hi Will,

> Symmetry Draw I LOVE IT!!!

Yeah, I think it will be a big help, even if it is just for drawing curves only at first.

It's one of the things that I hope to get done in v3.

- Michael

Sorry for my late reply, but I was not at the computer ... and the time to understand the explanations :-)

So thanks a lot for your answers.

I saw your model in your first file but it was not exactly than I would like when I try this :-)
For the rest, Pilou said everything for me :-)
I try this.