Hi Marc - so the reason why this result is confusing is because flow works on the underlying surfaces, not just on the visible trimmed area.

It looks like your plane was created by using the Construct > Planar command, which builds a trimmed surface and it puts the base underlying plane surface at somewhat larger size than the trim curves.

You can see this more clearly if you turn on control points for your base plane - when you do that notice how the underlying plane surface itself is actually a bit larger, like this:




That larger plane where you see the 4 corner control points is the thing that is actually used as the base surface currently, that's why the final result is not at the proportion that you were expecting.

If you use the ShrinkTrimmedSrf command (http://moi3d.com/2.0/docs/moi_command_reference10.htm#shrinktrimmedsrf) on that base plane it will shrink the underlying surface down to be snug to the trimming boundaries and then after that you should see a result more like you would have been expecting.

But also the way flow works is that it basically matches a kind of percentage along each surface, it's not going to do stuff like match a distance from the object to one edge to another distance, it's more like every point on the base plane goes to its equivalent percentage on the target surface.


Hope this helps explain the confusing result - I maybe should make the base and target surfaces automatically shrink down to fit their shaded visible boundaries to avoid this kind of confusing result. At the moment the ShrinkTrimmedSrf command will do that for you.

- Michael

It's all so clear now! ;-)

Ahh, it all make sense!

I did not know about this particular behavior of the "Construct > Planar command"
I will use "Draw solid>Plane" instead in this situation.

The results looks more of what I expected this way...



Thanks for taking the time to clear this up Michael.

This function opens up a lot of possibilities!

Marc

If the start object don't touch the surface, the end object on the target surface don't touch it also
Am i right?

I believe that is correct Pilou.

And it also looks like if your text (or start object) intersects the base surface, the result will intersect the target surface as well (rather than sit on top).

Ed

Hi Pilou,

> If the start object don't touch the surface, the end object on the
> target surface don't touch it also
> Am i right?

Yup, that's correct - the same distance of the start object to the base object will be applied to the target surface.

It's related to surface offsetting really - basically the distance of the starting object to the base surface becomes an offset distance that is used to make a point on an offset surface of the target surface.

- Michael

Hi Ed,

> And it also looks like if your text (or start object) intersects
> the base surface, the result will intersect the target surface as
> well (rather than sit on top).

Yup, that's correct too.

Also if you plan to boolean the resulting objects on to the target, it's probably best to make them intersect it a bit (like pushing down through it somewhat) rather than making them just skim right along the same surface area. That kind of barely skimming situation tends to be harder for the booleans to deal with.

If the booleans seem to get confused also try doing the boolean between 2 pieces at a time rather than as a whole group. Sometimes that can help - at some point I want to track that down and figure out why that helps in some kinds of situations.

- Michael

Here's a Flow test using text and a cylinder. The text intersects the base surface causing it to intersect the target surface. Joined cylinder surfaces to make a solid and Boolean diff to create engraved text. Quick render shown in corner.

"... I maybe should make the base and target surfaces automatically shrink down to fit their shaded visible boundaries to avoid this kind of confusing result."

Please do. This really messed me up until I read the explanation and fix. Guaranteed it will mess me up again :)

Ed

Hi Ed - by the way you can leave the cylinder to be a joined up solid from the start if you want. You can pick a face out of a joined solid as the target surface for the flow.

- Michael

There may be some benefit to the ability to still flow to the full underlying surface..

Hi Burr,

> There may be some benefit to the ability to still flow
> to the full underlying surface..

If there was built-in shrinking, you could still get the same current result with using the full surface by doing an "untrim" on the surface first before using it as the base or target surface for Flow.

- Michael

I am so jealous! ;-)

It could be useful to not have to disassemble the model to have the option.... (buttons, buttons, tick mark 1, 2 and 3 Burr)

Hi Burr,

> It could be useful to not have to disassemble the model to have the option....

You wouldn't necessarily have to disassemble it and reassemble it again - select the piece you want and do Ctrl+c to copy it to the clipboard, then hide the full model and paste in the piece that you'll modify and throw away when you're finished. Meanwhile the original piece stays as one whole thing so you don't have to reassemble stuff.

Let me know if you end up doing that frequently and those steps could likely be automated with a script of some kind.

On the other hand if it's something that you only need to do every once in a while then doing 3 steps or so instead of a having special option is not really a problem.

I know you guys like to have things done in fewer steps, but there is a tradeoff - it's not very good if you are presented with a giant panel of options making things look like a 747 control panel even if each button does some cool combination of what would otherwise take a couple of steps. When the UI gets clogged up with a ton of stuff a whole lot of other people aren't able to just run the basic stuff anymore because things tend to get lost in the mess.

But if there are things that you end up doing repeatedly in sequence, I can most likely cook up a plug-in that will help to streamline it for you.

- Michael

Ahahahhaaaa.. Short sightedness... I didnt even contemplate a simple copy and paste... Seems to solve it fairly well!!! :o

Hi Michael,

Only just got the chance to have a play with the new Beta & specifically I wanted to try out Flow.

Having read the posts within this thread, I figured I had a reasonably good idea on how it should/would work...
...so was kind of surprised to see the items mirrored or facing the opposite way around?
Not a big issue as I can easily rotate the ring 180 degrees, but more curious to know why this has happened & how to not do it again??
I'm assuming it'll be something to do with the various surface constructions & their directions???

regards Colin

Hi Colin, that happens when the u and v directions of one of those surfaces are swapped from what you want.

Right now the Flow command just maps from one UV space of a surface to the natural UV space of the other surface and doesn't yet have any options for controlling how they should be matched.

At the moment the easiest way to deal with that is to re-arrange your plane - squish your plane so that it is long in the other direction and then rotate the plane 90 degrees (and possibly flip it) and that should get you what you need.

That won't be necessary in the next beta though - in the next beta I've added a way to control how the UVs will match by paying attention to where you click on both the base and the target surfaces - you'll click next to an edge near one side of the edge, and then click on the matching spot on the target surface and it will then swap and reverse UVs as needed to make those spots be aligned.

So this problem should get better in the next beta - you'll just have to pay attention to where you are clicking on each surface.

- Michael

Hi Colin so actually in your case there it's not that the uvs need to be swapped, it's that you need the v direction to be flipped. At the moment you would do that by rotating the plane by 180 degrees around its middle along its long direction.

- Michael

Hi Colin, so here's an example for how it will work in the next beta.

You'll click near one corner of the base surface, near one side of it like this for example:



Then on the other surface you click on the equivalent spot where you want that to match up with, so you would click near this spot:



Then that will produce this kind of result:



So you won't click exactly on a corner - you click closer towards the edge nearby the corner to one side of the corner or the other side so there are 8 possible zones.

Anyway then it will swap or flip any UV directions as needed to make the output match those spots up.

- Michael

Hi Colin - one other note - with something like this where you want to have the deformed result loop around and have ends touching each other you will probably want to leave end caps off and then use Join on the result to glue those edges into a solid.

If you leave end caps on you'll have some coincident caps in the final result.

Also to make a good join make sure pieces that will touch go exactly to the edge of the base plane - one of the tubes in your example file here goes over the edge by a just a tiny bit (like 0.008 mm) but that's just enough distance so that it won't join to its partner when it is deformed. With that piece trimmed off then it will join.

- Michael