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Tips and Tricks by Users. Whether Advanced usage T&T or when fZ isn't playing nice... Add yours here!

¢hris £und

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Hello Z-gang!

Currently working on a WIP project.  In doing so, I am running into some situations where I either have to use some "probably" not well known techniques and in some cases where fZ isn't playing nice, but I need to achieve something specific any way.  

For this first one, the latter category. Adding a 2D wall to the inside, where fZ doesn't like to do it.


Here I have a shape that when I apply the 2D wall shape to with a wall width that is greater than what the acute angles allow for a clean offset (in this case, it is 4").


I get the following.  FormZ does its best here, but not what is needed.  Those orange loops aren't just visual artifacts.


At first, I split everything out and manually trimmed the lines then re-joined them for the shape I want.  Ends up being a lot of work when you have several of these to do.  In my case, some of them had more crossover loops (for lack of a better term.)

here is the solution.

Use the break tool in the 2D Edit menu. Break just 1 point so that your lines are no longer making a surface.



Now, apply the 2Dwall again, and it works they way you wanted in the first place.



That's it,  move on to your next task.


My original attempt at doing this, took about 3 hours (several of these shapes to do, each different.)  cleaning each curved line individually, extending, trimming, joining... many times it didn't go as planned, so redo, redo and redo.

I figured this out by accident.  I intended to break each of the curved segments up first, then do the trim/spits and joins.  Just for the heck of it, I broke the first point, and tried the 2D wall too just to see what would happen.   Simplified a lot.


If this thread ends up just being solutions to the "stumpers"... Document your solutions here.   Hope you guys want to join in.




¢hris £und

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So good! Thanks, Chris. I've run into a similar issue with crossover loops in the past and done the multiple hours of work to resolve the geometry. This kind of post almost deserves a dedicated work-around section on the forum!

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Thanks guys!  

Des, I didn't technically "think" of it.  It was on the path to what I thought was a simpler solution to what I was doing before. Just ended up being a lot simpler yet.

dpwr; It probably is ok here in the tutorials section.  But, the problem is being in the forum  at all.  Once something like this gets some traction, It may be best to filter the actual T&T from comments and dedicate a web page to.  Tech, if you are listening, I would be willing to moderate/edit a web page.

I have another related one I will post in a bit.

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Thanks for sharing your easy fix!

I'm trying to recreate the problem to see how I would solve it.  I know I've come across this from time to time and I believe I was able to just use the Object Doctor to fix it?  Did you try that?

Anyway, I'm having trouble creating the problem.  Maybe it's using all those points instead of Arc's?  Arc 5 is common for me, so that's what I used to make your example here, which worked as expected when using a 2D wall:


My other thought would be to draw the 2D wall from the beginning instead instead of Deriving it.  Simply tracing your shape or points with a Arcs and lines would create cleaner Smooth geometry, wouldn't it?  Maybe you are wanting to use Faceted instead of Smooth for some reason?

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Justin,   See what you get when you increase your wall size.  Just for the heck of it, try by a lot more.

Embarrassingly, I did not try the object doctor.  intermission...  Unfortunately, Object Doctor does not see that there is a problem.



Regarding your other thought,  In this case, shape that I got was a derivation from a master shape.  I did not create it from scratch. The master shape is what I am going for, so trying to recreate with arcs and manual lines would be challenging if it needs to be anything beyond an approximation. 

All the geometry began out as NURBS.






Here is a mockup before I decided to get technical with it.  The shape has changed a bit from this initial version.  Everything you see above and below are solids, down to the edge beading.  Below is a 20' craft, the above has been redesigned to a 16'.  If I ever get to build it, I can build a 16' in my garage.




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Did some more testing! 

This seems to only be a problem if you use Facetted modeling type instead of Smooth when creating the curves / wall.  If you start with the Smooth option, it works as expected.

Now, you mentioned it was NURBS to begin with, so I'm not sure how you make it smooth from there.  Can you convert the NURBS to a Spline?

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Thanks Des!  When I am done, I will offer it up here for free.  You architects will have free use of it for rendering, if you want to add some over the top to your already panache structure.  I am NOT and naval architect, so if anybody wants to build it, they are welcome to, but better think it through on top of what I am doing.

I will include the Starting Surfaces so the shape can be played with. As well as all the construction parts to as much detail as I end up creating.

Justin, The object is already a plain Object/Smooth.  Each section was generated from the Contours tool applied to a solid built up of stitched together NURBS surfaces.  Actually, to be more specific, the port and starboard surfaces are NURBS, the bridges between them are Ruled Surfaces. As, I planed for the tangents when I built the NURBS.

I have also attempted to generate a countour manually using the Surface Split tool. It generates "Composite Curve That can be converted to a NURBS object, but then, when I attempt to apply the 2D wall to it, it has its own problems.  Converting it again, to a plain object, the problems do not go away.

I have also attached the stitched together surfaces (it is solid) along with the contour surfaces. Back saved to Version 8.  There is an issue with one of the contours as it aligned exactly with the step in the hull.  Which is where I want it.  This was easily overcome by creating a section from the surfaces prior to adding the step.

Play away

Cheers!  ¢£



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Justin, you are correct though, about using the lines with Arcs.  It probably could be reasonably approximated with the Arc/Line tools.  But that once again adds a lot of manual work. Each Rib would have to be redrawn (At least from what I can determine) since none have the same curvature.  Your building of each, would need to be pretty precise to get a fluid curvature in the 3rd dim.

Despite that, it is interesting to see someone else's thought processes, so thank you!

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Oh, and I am looking at something like what is linked below.  I changed it a bit.  Simplified the water planing surfaces of the hull, as I don't intend on building a racing boat (even though, I included the step,) easier to build. Put a reverse rake on the bow, I just liked it.  Blended the freeboard with the transom. and the cockpit is a little farther forward than what is linked.  The freeboard on mine is a bit more complicated, so I guess I traded complications freeboard/planing surfaces.  

If I ever build this, and I want to, I am going to build a canoe and a kayak first to build some skills.  I will probably purchase some these plans and re-design my boat but pair up the technicals to the plans.  While I am doing the best I can to 'reverse engineer' from web photos... it is probably safer to admit I don't know what I am doing and just copy the what I can and still get the craft that I want.


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