> In this case i'm not sure how I would maintain the
> curvature while deleting center points

When you don't have very many points, you may need to use Edit/Add pt to place some more points in the area where 2 segments join with one another, so that when you delete the joint the shape doesn't change too much.

Also there are 2 modes for Add pt - if you have points for a curve turned on, then Add pt can add a point on the hull line in between 2 existing points. This keeps all the points in their same locations, and the curve will shift shape to go through those points.

The second mode for Add pt is when you click the point for it directly on a curve instead of on the hull line between 2 edit points. This is kind of easiest to do if the points are turned off since then you will only target this kind of add. With this mode the shape of the curve will remain completely identical and instead as the point is added it will cause a shifting of the control points instead of the curve. This is the mode that I used to insert a couple of points to either side of the center point so that when I deleted it the curve would not change shape so much.

I do want to add some tools in v2 to make it easier to merge segments together into new longer single segments instead of joined curves... That would certainly make it easier in this situation.

Also a symmetry mode so you can draw a single smooth segment just by drawing points on one side of a mirror line would also help stuff like this out quite a bit...

- Michael

Hi telnoi,

> thank you, I still have to get used to the idea that points in certain
> places will create more edges :(

It's not so much the points themselves (unless you used Add Pt with the "Make corner point" option), it is when you use Edit/Join to glue 2 segments together into one composite curve object.

With that curve being made up of 2 segments, many things will process it in a segment-by-segment basis, same thing as if you had a rectangle made up of 4 segments and extruded it, you will get edges at the ends of the line segments making up the rectangle. The same basic thing is happening here due to the segmentation even though the shapes are smooth to one another.

It could be possible for me to automatically fuse segments together in cases like this that have smooth pieces to one another, but unfortunately although that would have been better for this particular case, it tends to cause problems in a lot of other cases for mechanical objects, I was describing that some in this previous post here.

So to avoid those problems it tends to make things lean more towards segment-by-segment processing.

I definitely want to make some better tools for making single segment symmetrical stuff like this easier though.

- Michael

> I definitely want to make some better tools for making single segment symmetrical stuff like this easier though

That would most certainly be welcome. However, learning to construct models correctly in the first place seems to be a better learning method ;).

One last question related to this shape. Would it be possible to construct a base shape which would allow the construction of a 4 sided pyramid? In this case, the base needs 3 edges instead of 4, complicating the matter somewhat.

The curvature of the base shape is correct, but the amount of edges is not.



EDIT: never mind, managed to figure it out by intersecting a sphere with the old shape and using that base to construct the entire pyramid.

Hi telnoi,

You look like you are making it difficult for yourself.

Pilou put you on the right track by showing you to use the rail revolve, but, I do not think the intention was for you to produce the shape shown and then attempt to fillet.

If you progress from what was shown, you can produce both pyramids with a rail revolve without a need to fillet etc.

Hi Manz,
Is your bottom rounded also or flat? If rounded, how do you get it with reail R.

rail revolve couldn't be used to create the shape i needed, since the rail itself would have to be curved too ;)
So far, curved rails did not produce the result I was after.

Thanks for the tip though, it's appreciated.

>>since the rail itself would have to be curved too ;)


Both rail and profile are curved in the example I have posted. I also attached the 3dm file. Are you saying the shape I posted is not what you wanted? If not, then just edit the profile and/or rail.

>>Is your bottom rounded also or flat? If rounded, how do you get it with reail R

Just download the attached 3dm in that post. The rail and profile are in that file.

this is the shape I was after.

This is basically the last issue I'm facing prior to finishing my model.
I am again havving issues with a pyramid shape. The shape on the left was done using rail revolve, the shape on the right with lofting. The issue here is that both shapes have undesirable fillets. The picture explains the issues.



How can this be avoided? I have also tried just lofting two triangles that are not rounded, after which I applied a fillet, but that also seems to result in overlapping fillet edges.

Hi telnoi, fillet of a large radius going around a tight bend can generally be problematic.

Normally the way that I would recommend doing this is to start with the full blocky shape like this:



Then do the large radius fillet first:



Then follow with the smaller radius fillets afterwards, that order of large first small later generally helps avoid the kind of bunching that happens if you try to make a large radius go around a tight bend:



Unfortunately MoI's filleter currently runs into problems in this kind of "vanishing fillet" type situation where the fillet surface narrows down and ends in a single point like this (this is when the fillet surface does this, which is different from a corner piece between fillets doing it).

So this will require some kind of low level surgery to fix up.

What I did was to delete those messed up corners, and also the long fillet that was next to them.

Then I selected these 2 open edges:



And ran Construct / Blend to create a blend surface between them:



Then I selected the edges around the top open part and ran construct/Network to fill in that area.





There was another issue when repeating this for the 2 other sides, that the fillet had ended up trimming the edges in that area creating a small sized extra edge in there, so I had to select that edge and its neighbor and do Join before doing Network on those ones to get the full length in the Network.

The final result is attached as lastissue_2.zip, I hope it may be sufficient for you.

I am nearly ready to apply a geometry library update to the v2 beta, it seems to incorporate quite a few fixes for filleting so hopefully this should improve shortly. I'm not sure yet if it covers this kind of "disappearing" fillet surface to a point yet or not though.

- Michael

Ou la la, There is much simpler!!

Vincent

Toblerone Professor Tournesol advice :)

Pilou, that is what I did initially, but I required more control over the final outcome of the fillet shape itself. The client i am working for is very specific about these kind of details.

>And ran Construct / Blend to create a blend surface between them:

First time I used those tools :) seems they may come in handy fixing some other minor issues I was facing in the past. I am most certainly looking forward to the v2 update. Moi is such is a useful product, especially considering I learned to pick it up and do some decent work within two days. The final model would have been absolute hell to model in c4d, or any poly modeler for that matter.

or ......

Hi Vincent,

> Ou la la, There is much simpler!!

Definitely that is a more simple way! But all those rounds that you show there are of the same radius, it's a different shape than having a larger sized round towards the front and smaller rounding around the long parts.

- Michael

Yes, of couse !

But this !

Hi Vincent, yes that is more the right kind of shape!

But if you look at the corners you can see a kind of sag or ripple in the corner area. The fillet mechanism is having a difficult time filling in that corner, it is kind of a too-broad area for the corner-filling mechanism to handle.



- Michael

Hi Telnoi,

> First time I used those tools :)

Basically Blend and Fillet are the only tools currently in MoI that focus on constructing things that match smoothly with surrounding surfaces.

In the future I definitely want to add more options to different commands to enforce smoothness (often this is called "continuity" in NURBS modelers).

Like in this case it would have been better to have a continuity option in Sweep so that the long skinny surfaces could just stay in place and a 2-rail sweep could be done from the fillet edge down to the point.

Eventually those things will come, they are kind of a more "low level" type NURBS modeling dealing with surfaces more directly instead of the "high level" solids type methods.

The solids type methods are usually faster and kind of easier to use because they incorporate several kinds of "low level" tools applied in a bundle, but if they can't do the proper job in a particular case then it is good to be able to fall back on some of the individual "low level" type tools.

- Michael

>>this is the shape I was after.

So not like the shape you posted originally. (c4d image)