VariableFilletSrf only partially selects my surfaces

Hi
V5

Now this no doubt is me. I have a network surface and a sweep2 rail surface joined using what I am told is the correct way to join surfaces…ctrl J or join.

see creation of them in this thread

I have a planar area made of two curves , created from dupedge (then FitCrv to improve the curve) and a vertical line.

I wish to fillet a variable radiused edge between these as indicated in attached file, however as soon as I select first surface I only see the networkSrf part of it get selected. When I select the planar surface only a portion of it gets selected.
This was the case when I tried VariableCahmferSrf, thinking it was for radiused edges. silly me.
Now I try variableFilletSrf it remains selectd for a split second only and is gone.
I cant even get the image in the jpg that was from when I tried Chamfer.

Now the planar surface was made by Rhino, its not a join of 3 surfaces.

How do I firstly fix these surfaces together then will variable chamferSrf be the tool to use ?

More accurately how should I have joined my compound curve surfaces together ?

After Rhino created the planar surface, what should I have done to it ?

FilletEdge is for solids but this shape isnt to be a solid but remain as seen.

ChamferSeesPartial Surface.3dm (230.8 KB)

Steve

Hi

Even if you manage to fix these surfaces the chamfer will fail due the leading edge radius being smaller than the chamfer size.

Hi,
Thanks for reply…
Thats my mistake on that last radius…, plans indicated the last but one and I thought I needed one at leading edge so went for the same rad…oops !

Now I know what that rad should be.

That aside, how should these surfaces overseen by Pascal have been joined to facilitate such edge commands and other actions later on ?
The surface labelled by you as should be a planar surface was a surface created by tool surface from 2 or more curves, the curves were dupedge created from the surfaces you see cut through with a PLANAR surface formed from an extruded line.

if one cuts a surface such as this with a planar surface, why doesnt a planar surface result when dupedge and surface from 2 or more curves is used ?

Should I have used surface from planar curves tool ? I guess I grabbed the wrong tool, didnt spot the other one in the hurry.

So presented with planar curves, tool surface from 23or4 curves can create a non planar surface, i.e, cock things up a bit !
so it would seem. The dupedge it was given to use was festooned with points, lessened with FitCrv. They resulted from a simple straight cut across that networkSrf.

Break in surface continuity is where networkSrf result meets sweep2rail result. Both were run past Pascal and the forum as what is best approach. The NetworkSrf area looked super, the sweep2 and use of point looked ok…ish. I would like to know how they could be better produced at wingtips.

Cheers

Steve

Hi

This is how I do wing tips. The key take a ways are only trim surfaces when it’s absolutely needed and keep the trims as small as possible.

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Hi

This is the way to properly cap the end surf. Use surface / Planar curves select the edges and the end curve. The finished result is a perfectly trimmed planar surface. When it fails it’s most often because the input curves and or surface edges are not in planar alignment.

ah yes, the planar surface tool, I overlooked it as mentioned.

silly me.

Just tried it and wow, beautiful, why the heck did I overlook that ?
Trouble is I am working a 15 hr day on this.

also in another thread Skyg has said to create a planar surface then use the edge of my surface to trim it.

To do my tailplane tip then , I should treat it as two halves, your red and your blue.

see Attached the original one tweaked by Pascal. added back into it the tailplane tip which I proceeded to use sweep2 and point option, used the two tip rails.

I like your two halves approach but am unsure in my case how I get their junction…
My problem was I had no profile for the red.blue joint line.

What should I do there ? maybe sweep2 then create a profile from isocurve, tweak it etc, and then do the final surfacing, ditching the sweep one ?

Wing_Steve1b.3dm (43.3 KB)

Steve

Hi

I did my best to speed model it so it’s not up to my usual standards. It is water tight and the surfaces are continuous. I upped the file tolerance to .001 mm. I had to rebuild the loft curves because the cv counts did not match. That changed them slightly unfortunately. I use surface split at isocurve a lot with shrink on when I do stuff like this. Sweep 2 rail with maintain height and surface blend for the cap. Once you understand how to properly build curves including using the right degrees building clean surfaces is much easier.

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Hi,
Gosh,thanks a million.

addendum…Having typed out the response below earlier, I just opened your 3dm, I see we are missing the 3mm dia aft curved surface edge, and the outer edge is a tighter radius edge than that, when it should be 3mm also, else I could sweep it back in but unfamiliar with what you did here I cant until I get more knowledge. Is this something you were not able to accomadate in the rebuild ? I also see the leading edge has gained 2mm which when placed with the main part of the tailplane doesnt then follow on tangentially from tailplane leading edge. Now I wasnt expecting this and its a shame I cant drop it in and use it, the change to leading edge, given the correct techniques, if that is a result of such, I am unsettled on how I can adhere to the dimensioned shape if creating a better surface loses such. Did the need for Cv counts etc require such changes as if so, I am going to have fun…not !

cv counts, shows how much I have to learn, I am not aware of such…so I just googled that and cant find anything about its significance etc in rhino, no doubt its buried in a tutorial somewhere.
isocurves, knowing how to take my profiles created in a different era when they used actual cane splines and model them to Rhino standards. Trouble is I follow the dimensioned plans, and need the dimensions to match, as one item fits with another from another plan.
I get to see someone making a fictitious aircraft, but I have actual data to follow, it would be great to see a video on doing such and then improving it and skinning the results.
No doubt just learning 10% of how to work with curves will get me there, I want tutorials that cover every option available, I wish to understand this inside out, thats how I like to be.

Seeing the blue profiles and deducing that the green lines are also required.
I need to be aiming and hitting the target, dead keen to learn all there is to know, eager with it.
This sort of help is invaluable. It would be great to see a jing video of such.

Wish Rhino had a little corner of their website set aside to us aerofoil wing and fuselage makers, or an aviation sub forum :smile: full of such help and videos. That would be fantastic and encourage more modellers and aviation orientated users, flight simmers, all sorts.

I just need time out from this mad job to do so.

Something with various exercises would be good. Something with an end result I can compare mine to.

Skyg has given me a link to his article on profiles, here it is should anyone and yourself find it useful.

I will be redoing my main tailplane profiles to this now, even if it does wipe out my original planned Saturday and put me back another day.

Some of the drawings I have to work with are atrocious, like soot was spread over the copier glass !

I need to learn about keeping to the profile data table shape yet making the profiles rhino friendly. Cant go altering shapes much, though its not going to fly. 0.3mm here or 0.5 there isnt going to matter. having the result bite back and cause issues later does. Hence a redraw today.

What graphical analysis were you using in the earlier black/grey screenshot ?

surface splitting with shrink on…I need to be seeing tutorials that cover such things and why that is best etc.

Fully agree, Before I started rhino V4 I had two printed out pdf’s from the training that came with and read them through page by page, making sure I understood each page. It seems to have missed out on so much. I will be looking at what is offered for V5 beginners, pdf’s videos, wherever they are, and i am not sure where they are at the mo, so will be off searching as soon as I can !

To be able to focus on those of use for wings and such like would be good if I can find any.

Steve

Hi,Stratosfear,
how did you come to draw the green lines. I have refined my curves, cv 20 for each, I wish to follow your lead and get those green lines in but what were the steps taken as far as those ?

did you do a rough surfacing then use icosurves and establish them then reskin again in panels with those as the edges ?

Steve

Those green lines are not curves they are the surface edges. The blue lines are your curves. I used Split at isocurve to trim back the main body of the wing. To create enough room to smoothly blend the caps. I split it again to create the leading edge surface to blend the corner round into the 2 rail sweep end.

Explode the polysurface and turn on the control points to better understand the topology. I use split and shrink a lot. There is only one trimmed surface. A small section of the main wing to join the corner blend.

Hi,
Think I can visualise that,
Q1) am I right in saying the key thing is not to have a 3 edged surface but a four edged one, the tailplane tip using sweep and its point option is bad practice and creates a 3 edged surface.

Its chicken and egg, one needs the surface so as to create the ‘green lines’ to use for a better second sweep.

Q2) Is that the principle,…create a surface, use it for better lines, avoiding 3 edged surfaces, zap it then create those better surfaces ?

Q3). Just trying to establish if you used networkSrf to get a surface to use isocurves from and create better rails, or if you used sweep2 and point option for the tip, whichever gives the better isocurves I guess.

I have curvature graphed every curve, the original data for the profiles had a dip in and out near trailing edges.
Sweep2 though doesnt produce as nice a spaced isocurve result as networkSrf, i was surprised at that in fact.

I have treated the edge which has a radiused edge aft of tip centre to a separate sweep using the radiused curves, then dupEdged it to get the outboard rail for the surfacing inboard from that.

I can see the green lines you created each give a four edged surface.

Q4). Four edges are better to surface than three. is that standard good practice or your preferred way ?

Each profile has 20 points, had to redraw the one nearest tip as it had 17.

I also have drawn between these points heading out to tailplane tip using InterpCrv (the original points picked when using InterpCrv) should such be of use in surfacing. I tried for NetworkSrf with and without them, I had better curvature without them oddly enough and have created a few port to stbd profiles. I find that sweep2 gives a sunken fabric effect whilst a lattice of profiles gives a decent looking surface.

Cheers

Steve

Three edge surfaces are to be avoided whenever possible. The point where multiple cv’s meet (singularity) creates surface ripples. These points can bomb fillets, create surface matching issues and cause thicken surf and shell commands to fail. Sometimes they are unavoidable but there are ways to deal with them by trimming out the singularity if needed. Yes, 4 edge surfaces are better than 3.

I never use netwerk surf. It creates cv dense approximated (rebuilt) surfaces that just aren’t accurate / smooth enough for what I do. Turn on zebra strips and you can easily spot a netwerk surface.

Surface modeling is very difficult. There is no one approach that will work for all topology. That’s why Rhino has a laundry list of surface tools. With experience comes the ability to recognize which approach is best to use.

Your issues with the sweep and loft commands is directly related to your curves. They require matching cv counts for the input curves to work properly. You can use the built in rebuild option to create an approximated surface like netwerk surf does. But the results often aren’t all that great. Especially with cv dense curves like yours.

Your fanatical obsession with the accuracy of curves. It’s causing you so many bigger picture problems. Your idea/understanding of accurate curves does not support the greater goal of creating smooth accurate surfaces. This is even more maddening considering your source material is scanned 70 year old plans. That were used to create hand built parts in a production line. I’m not sure what your finished model is being used to create. I suspect from you having mentioned hand sanding that total accuracy is not the order of the day. You hopefully will understand this once you take a breath and really apply yourself to learning nurbs modeling.

Everyone here is happy to help with specific problems. We all need help from time to time. It gets really frustrating when people refuse to take the time to learn the fundamentals. That will enable them to understand what they are being shown and told to do. It means we have to keep addressing the same issues over and over again.

Hi,

Q1) am I right in saying the key thing is not to have a 3 edged surface but a four edged one,

A…Three edge surfaces are to be avoided whenever possible.

Cheers

Q2) Is that the principle,…create a surface, use it for better lines,
avoiding 3 edged surfaces, zap it then create those better surfaces ?

A….???

Q3). Just trying to establish if you used networkSrf to get a surface to use
isocurves from and create better rails, or if you used sweep2 and point option
for the tip, whichever gives the better isocurves I guess.

A… I never use netwerk surf. It creates cv dense approximated (rebuilt) surfaces
that just aren’t accurate / smooth enough for what I do.

Ok

Q4). Four edges are better to surface than three. is that standard good
practice or your preferred way ?

A… Three edge surfaces are to be avoided whenever possible. The point where
multiple cv’s meet (singularity) creates surface ripples. These points can bomb
fillets, create surface matching issues and cause thicken surf and shell
commands to fail. Sometimes they are unavoidable but there are ways to deal
with them by trimming out the singularity if needed. Yes, 4 edge surfaces are
better than 3

Ok.

Your issues with the sweep and loft commands is directly related to your
curves. They require matching cv counts for the input curves to work properly.

I have redrawn that which had 17 to be 20, using the same points
distribution (half cosine or whatever the designers were on.)
They all now have the exact same proportional spacing of points that are drawn
through with InterpCrv.
See thread


for method and image. They are all now treated to curvature graph and corrected, all needed correction at trailing
edge and one also near leading edge.

your source material is scanned 70 year old plans

No, I am not tracing a scanned curve, for these it was aerofoil paired dimensions from a table, distance x (from a common datum …elevator hinge datum) horizontal then at that point ot from datum use the distance up
from chord axis dimension. When plotted and drawn with InterpCrv an aerofoil section results. Such is normally followed without question, good reason must be used to deviate from that curve. As such tweaks enough to give a good curvature graph are ok, altering it significantly when it is supposed to be ok for flight characteristics sees a pause for thought.

Your fanatical obsession with the accuracy of curves. It’s causing you so
many bigger picture problems.

Eh ?.. fanatical obsession with the accuracy of curves … that doesnt equate…I am being told I am not accurate enough ! , so I am now seeking to improve my methods and accuracy to meet such advice ! I just want to do enough
work so that the surface is ok and the curve is ok. No more than that. The final product being for static purposes does not warrant effort and time involved to 0.01mm and perfect surfaces but its not possible to build in rhino without
them. An imperfect surface creates curves with far too many points which denies me filleting etc. so one has to be accurate, like it or not. This is where we came in. My curves were not accurate, as opposed to me being obsessed with
accuracy.

It gets really frustrating when people refuse to take the time to learn the
fundamentals.

I hope that is not aimed at me as I want, repeat WANT to learn all there is
and know it inside out, I am having to struggle through as THERE IS NO TIME AT
ALL TO BOTH LEARN AND DO THE CURRENT JOB, I have stated my predicament before…
I am working a 15 hr day on it 7 days a week and until its done will I get to do what I want to do and that is redo levels 1 and 2 again. I am so looking fwd and desperate to get the tutorials out, hope folk can understand the sheer frustration of not being able to do so, yet be expected to know it all already to get the job done. But for this job I would have time to do the learning I want to do.

I have degree3 curves which adhere to the original points the sections should go through and are correctly drawn now with InterpCrv ( I always use InterpCrv) and pass inspection with CurvatureGraph. If I sweep2 these and get isocurves with some bunching I am at a loss to know why.

I try not to post dumb questions, the forum apparently is not for learners, if I dont get help with what I hope are fair questions I will never get this job done and be unable to get at the learning phase again.
I am however learning that there are tools that shouldn’t be used, and such
advice does not come across in what there is to read, such as joinEdge, networkSrf etc. also don’t trim surfaces. Having come across these tools in my first and only learning session I am now learning (being told) not to use them without good reason.

I am still here just trying to find out does one create chicken or egg, make a surface then get curves from it to then create four edged surfaces then make it a second time with these curves. Is that how the green curves were
established ? One cannot create such from thin air ?

i.e my question number 2.

Thanks for help given, really am most grateful, sorry for any dumb questions I might ask.

Just need to know Answer to Q2.

Maybe we need a thicko’s section for beginners. For all those able to first learn Rhino then start a demanding job think yourselves lucky.

Cheers

Steve

I create surfaces to build additional surfaces off of. That way I can use them to ensure the continuity of the new surfaces built with sweeps and blends etc.

I sometimes duplicate the edge of a surface to use it to trim another one. Then Match surf it to the newly trimmed surface. Trimmed surfaces are a last resort. You should try to keep them small. They’re for the proposes of attaching a 4 sided surface. This method is used to fill in areas that would require 3 or 5 surface edges.

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Stratosfear,
Cheers.
I want to shut the doors on the world and get as good as this.
This is what I suspected, and now to know, will be of great use…

Do you ever use VSR plug-in or anything else or just native rhino tools. ?

See my other thread in fact, having by chance spotted what looks to be very useful.

Steve

I would not necessarily state that as an absolute law.
Also see posts 19 and 21 in this thread: