Webbed dish 4285 sub-part

[Peter Agardi]

Hello!

I'm very new and definitely not versed in this community, please disregard my ignorance and naivity as a noob.

A story: I build the 6398 Police HQ in Studio for nostalgia; upon rendering it the blue webbed dish looked a tiny bit angular, lacking angular resolution. I dig deep, how parts are made, how this LDraw works, tried LD Part Editor, used spreadsheets and ultimately "updated" the 4285s01.dat sub-part. I tried my best to keep CCW orientation. There are minor coplanarity issues with it (can't spot it on renders) and I can't comprehend command line 5, so I did not touch those.

If someone has the time to take look at it, have the knowledge and will to correct it (if needed) would be nice, especially if this could become an official part later on.
Part attached to this post.

[Willy Tschager]

Hello!

I'm very new and definitely not versed in this community, please disregard my ignorance and naivity as a noob.

A story: I build the 6398 Police HQ in Studio for nostalgia; upon rendering it the blue webbed dish looked a tiny bit angular, lacking angular resolution. I dig deep, how parts are made, how this LDraw works, tried LD Part Editor, used spreadsheets and ultimately "updated" the 4285s01.dat sub-part. I tried my best to keep CCW orientation. There are minor coplanarity issues with it (can't spot it on renders) and I can't comprehend command line 5, so I did not touch those.

If someone has the time to take look at it, have the knowledge and will to correct it (if needed) would be nice, especially if this could become an official part later on.
Part attached to this post.

Welcome to the forums. I had a quick look at your work which is already heading in the right direction. If I had to rework that dish I would generate a 96er edge prim with PrimGen2 in LDPE as a guideline.


  4-4edge.zip (Size: 986 bytes / Downloads: 2)

and save it in LDraw\p\96

I would then use this ultra hires prim in the part:

1 16 0 10 0 60 0 0 0 1 0 0 0 60 96\4-4edge.dat
1 16 0 16 0 60 0 0 0 1 0 0 0 60 96\4-4edge.dat
1 16 0 16 0 57 0 0 0 1 0 0 0 57 96\4-4edge.dat
1 16 0 7.5 0 54 0 0 0 1 0 0 0 54 96\4-4edge.dat
1 16 0 9.9 0 55 0 0 0 1 0 0 0 55 96\4-4edge.dat
1 16 0 10.75 0 57 0 0 0 1 0 0 0 57 96\4-4edge.dat

1 16 0 3.5 0 42 0 0 0 1 0 0 0 42 96\4-4edge.dat
1 16 0 5.5 0 42 0 0 0 1 0 0 0 42 96\4-4edge.dat

1 16 0 2 0 36 0 0 0 1 0 0 0 36 96\4-4edge.dat
1 16 0 4 0 36 0 0 0 1 0 0 0 36 96\4-4edge.dat

Add radial edges:

2 273 23.204 0 -4 59.872 10 -3.924
2 273 23.204 2 -4 56.878 10.75 -3.728

And calculate the intersection point in LDPE with the edge of the prim as main target for the calculation:

0 !LPE VERTEX 53.844 7.5 -3.959
0 !LPE VERTEX 41.786 3.5 -4.002
0 !LPE VERTEX 35.759 2 -4.011

You'll see that those differ from the current vertices, which surely have been calculated with a 48er prim as base.

w.

[Peter Agardi]

Welcome to the forums. I had a quick look at your work which is already heading in the right direction. If I had to rework that dish I would generate a 96er edge prim with PrimGen2 in LDPE as a guideline.

You'll see that those differ from the current vertices, which surely have been calculated with a 48er prim as base.

w.

Hey, thanks!

On first reading a couple hours ago I was like "WTF is he talking about?!", I'm really not versed in this stuff but I read it again, trying to follow your chain of thought and I'm definitely getting there. However, I'm not quite sure what's your advice about. Correcting the coplanarity issues by calculating the intersection points? That could help, I guess!
I was approaching the thing in quite a naive way: I manually subdivided the 32 segment original: the inner ring's big segment into two (getting a 64 segment circle) and dividing the outer ring by 3 achieving a 96 segment circle. The radial's vertexes were "fixed" in my mind I just draw triangles and modified the quad's coordinate to that vertex that I considered "fixed".

If I may ask a question: what's the meta now? Do you still use rect.dat files, or is it okay to just draw quads and add lines? I can certainly handle that quite easy, tbh, but I have no idea how to handle rect.dat references. And for extra honesty here: I'm satisfied with the renders I got, I only uploaded this file here for the sake of community if anyone ever want to touch up this sub-part. 
If I go deep should I:
- try to recreate the part OR
- just correct the coplanarity issues?

[Willy Tschager]

Hey, thanks!
On first reading a couple hours ago I was like "WTF is he talking about?!", I'm really not versed in this stuff but I read it again, trying to follow your chain of thought and I'm definitely getting there. However, I'm not quite sure what's your advice about. Correcting the coplanarity issues by calculating the intersection points? That could help, I guess!
I was approaching the thing in quite a naive way: I manually subdivided the 32 segment original: the inner ring's big segment into two (getting a 64 segment circle) and dividing the outer ring by 3 achieving a 96 segment circle. The radial's vertexes were "fixed" in my mind I just draw triangles and modified the quad's coordinate to that vertex that I considered "fixed".
If I may ask a question: what's the meta now? Do you still use rect.dat files, or is it okay to just draw quads and add lines? I can certainly handle that quite easy, tbh, but I have no idea how to handle rect.dat references. And for extra honesty here: I'm satisfied with the renders I got, I only uploaded this file here for the sake of community if anyone ever want to touch up this sub-part. 
If I go deep should I:
- try to recreate the part OR
- just correct the coplanarity issues?

Hi,

It is perfectly fine if you leave the part as and where it is now - but you could also see it as a challenge or a chance to learn new things. We are not new to guiding people through this process:

https://forums.ldraw.org/thread-27965.html
https://forums.ldraw.org/thread-27173.html

As for the "Rects," you asked the wrong person: I do not like or use them, and I’ve stopped reviewing parts that contain them. Nowadays, rects are in our code because of "Rectifier." No one would or could calculate a rect (especially a rotated one) manually if wasn't a program that does it for you. I think rects are fine on a standard grid to help with authoring, but they shouldn’t be in the final code.

If you want to continue with your work: Redesign the joints where the rings meet the spoke using the 96-piece part and the intersection I posted above and come back when you're done.

w.