How to choose the right 3D material for the background you want to draw: Line art edition

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ldl

ldl

Introduction

I think it's very important to choose 3D materials that match the background you want to draw, so I'll write about that here.

It's long, but I think it will be useful to keep it in the back of your mind, so please read it if you'd like.

I also create 3D materials, so I will include that perspective in the article.

 

↓I have a variety of items for sale that may be useful, mainly for monochrome manuscripts, such as 3D materials.

 

It's probably not for beginners.

There aren't many detailed explanations about basic operations.

Please refer to the user guide for information on operation.

The content is purely my personal opinion.

Also, this time it is for monochrome manuscripts.

It may be different for color manuscripts.

 

These are my personal opinions that if you want a background like this, then this material is recommended, but it in no way means that this material is no good...!

The same material may be recommended or avoided depending on what you are looking for.

I'll be writing all this arrogant stuff about recommendations, but materials are all too precious to begin with.

 

It is often the case that you can't find a niche material even if you look for it.

If you do find even just one, dance a dance of gratitude and download it.

 

For example, there are probably plenty of materials for the characters' homes, workplaces, and schools, so these are suggestions on how to choose materials when there are many options like that.

 

 

Generally speaking, it's a good idea to keep in mind the following points when searching:

 

Smoothness of curved surfaces (affects line drawing)

 

Material (affects tone)

 

 

In this TIPS, I'll explain the parts related to line drawing.

I hope to create some TIPS about tones later.

Lightness of movement or smoothness of curves?

First of all, the more complex the 3D material, the larger the file size, so depending on your work environment, it may be too heavy and not run properly.

This will vary depending on the computer or tablet you use, so it's difficult to set a clear standard.

The file size is not listed on the material's description page, so it's hard to judge.

I think this is a difficult issue.

 

To briefly explain, 3D is made up of flat surfaces.

Curved surfaces are also a collection of flat surfaces.

 

For example, if you look at a sphere primitive, it's easy to see that it's made up of small squares and triangles.

The finer these are, the smoother and more beautiful the surface will be.

However, the smoother it is, the more squares and triangles there are lined up.

Naturally, the more squares and triangles it is made up of, the more information there is and the heavier the data will be.

The number of polygons, vertices, and file size will increase.

The lower these numbers are, the lighter the operation will be, and the higher they are, the heavier the data will be.

It's fine if it's just one sphere, but if it's made up of many things, such as 3D materials for a room, it will become heavy if you are too concerned with the beauty of the curves.

 

For example, I once lined up 3D food materials in front of the characters, and the operation became extremely slow.

When I checked, I found that the 3D food material was very elaborate, which means it was a heavy material.

It would be fine if it was just one material, but when I lined up multiple materials, the operation became very slow.

It is a very useful material that can be converted very beautifully in close-up scenes of food, but when I lined up a lot of them in a scene with the camera pulled back, the operation became slow.

It is very difficult to balance here.

I think it depends on what you prioritize.

 

The more jerky it is, the lighter it is, so I recommend it if you want to prioritize light operation.

I think it is especially good for people who draw using 3D materials as a rough guide.

Slow operation can be stressful after all...

Jagged edges are convenient for light operation, but after LT conversion, the jagged lines make it look like a 3D material, and additional touch-ups or corrections are required.

 

By the way, when I create 3D materials, I try to avoid adding touch-ups as much as possible, so I make them with smooth curves, so I don't think they're suitable for people who want a light and easy-to-use feel...

However, since the majority of 3D building materials have straight lines, I think it's unlikely that they will reach a state where they won't work properly.

 

For fellow lazy people who don't want to add touch-ups even after LT conversion, I recommend materials with smooth curves.

 

 

If you value smooth operation, choose a jerky material

 

If you don't want to bother with retouching, choose a smooth material

 

It's a good idea to keep this in mind when searching.

 

 

About the smoothness of curved surfaces

Even when talking about a smooth material, it is difficult to define what constitutes a material with smooth curves.

After all, it is a collection of straight lines, so it will look jagged if you get close.

It is also a good idea to keep in mind how much you might enlarge the material and use it.

For example, if you don't want to make any additions or corrections, the size of the flat circle in the image below with 24 vertices is a little unreliable.

However, for example, I think 24 is too many screws to add a little detail.

The screw in the image above has 24 vertices.

Even if I reduce the number of vertices, I don't think it will be enlarged enough to look blocky, so I would like to create these by shaving them down.

The standard circle is 48.

 

I think people who create 3D materials probably create them with this in mind, so it might be a good idea to find a material creator who has the same sensibilities as you.

 

Check the curved surfaces in the example images on the material description page.

 

However, materials with beautiful curves may slow down the operation, so be prepared for that, or take measures such as using a high-performance computer.

I'm not familiar with equipment so I can't give you any advice on what kind of performance is specifically good...

Sorry...

 

 

About PC

I hope this will be helpful.

 

This is just my personal impression, as I don't know anything about computers, but it's as follows.

 

I use a regular Mac desktop computer that I bought at an electronics store, with 40GB of memory (probably more than normal...?).

 

I heard that more memory is better, and adding memory is an easy thing to do, so I just did that.

 

Everything else is normal, so I don't think the processing speed is that fast.

 

I've had some stressful moments, such as the LT conversion waiting time or the operation not being smooth, but I've never come across a 3D material that caused Clip Studio to crash or stop working properly.

 

But there have been times when it crashed when I opened it on my iPad, so maybe most of the materials are just a little slow on a computer...? I think.

 

In most cases, the creators of large-scale 3D cityscapes and other heavy-looking materials have clearly stated that the data is heavy, so it's important to read the material description page.

Kind material creators often list the number of polygons, vertices, and file size, so you can also refer to these.

 

I'm an unkind person who doesn't list information on the materials I list...

I'm sorry...

 

 

About extremely jagged materials

You may come across 3D materials in Clip Studio Paint that have extremely jagged surfaces, but I think there is a reason for this.

 

Depending on the 3D production software, it is possible to set the surface to be jagged but smooth in appearance.

 

For example, all it takes is a lightweight jagged sphere + settings to make it look smooth, so this is a convenient feature that makes the resulting image lighter than if you were to actually create and place it.

It appears smooth due to the lightness of the jagged data (probably).

However, I think that the settings are very unique to each 3D creation software.

I don't fully understand it either, but I wonder if the settings are incompatible? I use CLIP STUDIO MODELER to make 3D materials for Clip Studio Paint, but I think that the setting to smooth out the jerky edges is disabled when I load it there.

Or maybe the setting is lost when I export it in a file format that can be loaded by MODELER?

 

And this is just something I've thought as an amateur, but it might be a bit of a hassle to process the jerky edges to display them smoothly.

It might be that doing so slows down Clip Studio Paint, or that it's difficult to update the software to support it, or something like that.

 

Sometimes images are posted on the material description page in 3D creation software.

In that case, the curved surface may be beautiful, but when you download the material for Clip Studio Paint and actually use it in Clip Studio Paint, you might think, "Huh? It's jerky...?" So if you value smooth curved surfaces, I think it's a good idea to check this before downloading.

If there are images of the operation screen in Clip Studio Paint or LT Conversion, I think it would be best to check them.

 

I think you have to be careful about uploading images that look good rendered in 3D production software.

I personally don't recommend uploading images that may give the mistaken impression that they will be displayed in Clip Studio Paint as well...

 

 

3D materials are for Atari or LT conversion

When using 3D materials for backgrounds and small items, the first difference is whether or not to use LT conversion.

 

1. Hand-draw using 3D materials as a rough guide

 

2. Add retouching after LT conversion

 

For 1, you can choose any 3D material.

 

However, if you want light movement, you should look for materials with less jagged curves and detailed work.

 

For 2, the choice depends on how much retouching you are willing to do.

 

As mentioned above, light movement and smooth curves are important.

 

If you use LT conversion and want light movement, I personally think that if the material is jerky, it gives a strong impression of using 3D materials, so I would like to fix it.

 

If you think, "It's jerky...?" or "Oh, it's a 3D material," the background will become a noise when reading the manga.

Personally, I don't use 3D materials to cut corners, but to reduce the time it would take to draw something from scratch, and use that time to improve the quality or to ensure I have time to rest so that I don't have to work too many hours, so I would like to avoid using 3D materials to lower the quality of my work.

 

 

How to deal with jerky LT conversion

I'll write down what I do to deal with this.

 

 

Smooth (Smooth)

First, when converting to LT, increasing the value of Smooth (Smooth in ver3.1 and later) seems to reduce the jerky sound.

↑It will look something like this.

The top row is a sphere primitive, and the bottom row is the tire part of the official "Luxury Car_By Layer" material.

It may be difficult to see any changes until you get to about 5.

Even at 10 there is no change and some parts remain jerky.

Still, the jerky is reduced in some places, so I think it can be quite effective if used well.

However, sometimes the lines become strange, so while it's fine for small items, you need to be careful when using it on large areas such as backgrounds with a variety of different objects mixed together.

In the image above, the seat is very plump at 10.

I don't know what conditions are likely to create this type of curve, but sometimes when you are trying to smooth out jagged edges, something else ends up with an extremely curved shape.

When this happens, the tone also becomes off.

 

My personal feeling is that straight lines mixed in with curved surfaces tend to look rough.

 

Previously, I would turn on Smooth at a low value when performing LT conversion, but I felt that there was almost no effect at low values, and in some cases, even Smooth 1 would make the lines rough in unexpected places, so I have recently turned it off.

I turn it on when I specifically want to smooth out some jagged edges.

When Smooth is on, it is a good idea to check whether there are any rough lines after LT conversion.

 

If you are not careful, you may realize in the middle of the finishing work that "the lines here are strange!", so be careful when using Smooth.

 

 

Control Points

If the line drawing is a vector, I personally recommend reducing the number of control points when smoothing it out after LT conversion.

When a line is particularly jagged, there are often two control points close to each other, so I think deleting one of them will make the line less jagged.

However, this won't work for cases with a lot of control points, like the sphere in the image above, so I think it's better to gradually reduce the number of control points.

↑This is what it looks like after deleting the control points.

It was a quick edit so the shape of the circle is a bit off, but at least the jaggedness is gone.

If there are a lot of control points or no other lines around it, like in the image above, you can use "Simplify vector line" to reduce the number of control points all at once.

↑It may look like this immediately after drawing, but you can eliminate the jerky lines by moving or, in some cases, adding control points.

 

The trick is to reduce the number of control points as needed depending on the situation, and then make fine adjustments.

 

I've written a lot, but if you don't want to bother tweaking the control points one by one, it may be quicker to erase the jerky lines and redraw them.

However, not only redrawing but also the smooth settings and control point adjustments only affect the lines.

Even if you straighten the lines, the tone will remain jagged.

So if there is a misalignment with the tone, you will need to correct that as well.

 

Dealing with this is also quite a hassle.

For that reason, for my lazy comrades, I recommend materials that already have smooth curves and do not require any corrections.

Especially when it comes to backgrounds for serialized works, I think it is important to prepare materials that require minimal corrections for places that appear multiple times.

 

 

Figure out how much editing is needed

For those of you who are too lazy to even add any retouching after LT Conversion, you should think about whether it will look good in the foreground.

For example, if you pull back the camera in the background of a classroom, there will be a lot of chairs and desks in the frame, so it will look pretty good with a lot of information.

The objects will be displayed small, so the jerky lines will be less noticeable.

↑There is some slight jerky movement, but I think this can be resolved by using Smooth.

The example image is the official material "Classroom Corridor 01-Ver.2".

So when the camera zooms in on a single chair, the amount of information inevitably decreases.

Furthermore, if there are any jagged edges, the larger the chair is displayed, the more noticeable they will be.

It's important to check whether the image still looks good even when the camera zooms in, and whether the jagged edges of the curved surface are noticeable.

In the image above, the jaggedness is quite noticeable.

You should consider whether this is within your acceptable range.

If you use Smooth, the jaggedness of line art can be improved.

In the above image, it is Smooth 4.

However, as shown on the right, when you display the outline of tones and textures, they are jagged and need to be corrected.

In this case, if you are only using line art during LT conversion, Smooth can handle a large part of the problem, so I think it can be used sufficiently even when the camera is close.

For those who want to use tones without correction, it may not be very reliable.

 

It's a good idea to check these points.

By the way, if you get the smooth setting wrong, it may look like the image below.

↑This is Smooth 10, but depending on the material, Smooth 1 may make the lines rough and you may not be able to use Smooth effectively, so it's important to check beforehand if you are going to use Smooth.

 

 

Presence or absence of texture and ease of retouching

It's also a good idea to determine whether you can easily increase the amount of information.

For example, if there are curved areas where you cannot rely on the perspective ruler, like the red framed area, it would be difficult to draw in the wood grain.

This is all the more true in scenes with lots of chairs lined up.

You want to determine whether there are any, or only a few, such areas.

You're lucky if there is texture included to begin with, as in the image above, but even in that case, if the camera is extremely far or close, the texture can be crushed or jagged, making it difficult to come out cleanly.

↑In "Classroom Corridor 01-Ver.2", it was difficult to make it look like a monochrome manga, even when I adjusted the wood grain texture of the chair.

 

↓Here are some recommended methods for adjusting textures.

↑The backrest and seat are made of boards with no curves, so if you use a perspective ruler you can quickly draw in something that looks like wood grain, so I think adding to it will be easy.

However, if there are a lot of chairs and desks, like in a classroom, it can be quite difficult to draw them in one by one, so I recommend considering whether this is within your acceptable range.

Personally, I think that the more desks and chairs you have, the more efficient it is to use materials that have "texture (ideally suitable for monochrome manuscripts)" and "color range selection that allows you to select a texture".

However, if you are combining many 3D materials, it may not be very effective if you have to switch materials multiple times...

 

I think this is a minority among the materials listed on ASSETS, but it is convenient because you can select and adjust the texture part all at once with color range selection.

I try to do this as much as possible for the 3D materials I create (materials I created a long time ago do not have color range selection available).

 

 

If you're going for a simple style without adding textures, the line art alone needs to look cool, so it's all about how beautiful the line art is.

The simpler something is, the more noticeable any roughness is, so it's best to check it carefully.

It's important to choose materials that can be used without any modification, such as using smoothing or adjusting the control points a little.

 

It's important to try and see if you can quickly fix any issues with additions and corrections, and whether they're within the acceptable range.

Bonus - About normals

This is just a bonus.

And since I'm self-taught and don't really understand 3D, this is mostly just my speculation and may contain complete lies...

Please keep that in mind when reading.

 

This is a different perspective on the issue of whether a curved surface is jagged or smooth from the issue mentioned above.

First, use "CLIP STUDIO MODELER" to set up 3D materials for Clip Studio Paint.

You will be setting up a 3D object, but the way the normals are set in MODELER will affect how the lines appear during LT conversion.

Since this is something you set in MODELER, and you can't do anything about the downloaded materials, this information may not be of much use even if you know it.

Therefore, I'll write it here as a bonus.

 

 

About "Recalculating normals"

To be honest, I don't really know what normals are, but in MODELER there is something called "recalculate normals".

This is probably a setting for whether the edges of the 3D material (red line in the image below) are defined as corners or curved surfaces. Probably.

 

The lower the value you set for recalculating normals, the more likely it is that the edges are treated as corners, and lines are often picked up.

If you use LT conversion on a sphere with a value of 0, the line drawing tends to look like a mirror ball.

Lines are particularly likely to appear on jagged surfaces.

If you want to make the curved surfaces of such materials smooth using LT conversion, you can reduce the number of lines drawn by lowering the detection accuracy value.

However, during LT conversion, minor unevenness is difficult to reflect even with high detection accuracy values.

For example, in the image below, the left side has a detection accuracy of 100, and the right side has 50.

At 50, there are some places where the lines are not clearly visible.

↓After LT conversion

←Detection accuracy 100

→Detection accuracy 50

Therefore, for materials with low normal values, you may be faced with the dilemma of whether to prioritize increasing detection accuracy to bring out fine lines clearly

 

lowering it to eliminate curved surface lines

 

.

Personally, I think that setting the normals in MODELER to a nice setting and then setting the detection accuracy in LT conversion to around 95-100 makes it easier to get nice lines.

But sometimes the settings aren't as straightforward as you'd expect...

 

 

About adjusting normals

To prevent curved surfaces from becoming like a mirror ball, it is not enough to simply set high normal values to make them smooth.

 

For objects that have a mixture of straight lines, curves, and surfaces, if the normal values are high, a hazy shadow with diagonal lines will appear on the flat surfaces.

This will result in a slightly subtle tone during LT conversion.

 

↓An example of a hazy shadow even with high normal values

↓An example of a good normal

I think it's because they define the jagged parts as curved and process them forcibly, which makes the surfaces look blurry and strange.

Maybe.

 

As mentioned above, even with high detection accuracy, minor unevenness is difficult to reflect during LT conversion.

I will explain how to adjust normals using the object below, which has both bumps and curves, as an example.

↑If you make a slight dent like this, it will be difficult to get that part to come out well during LT conversion.

If the normal value is low and the detection accuracy is high, extra lines will appear on the curved surface, and if the normal value is high, even with high detection accuracy the dented part will be determined to be curved and lines will be missing.

 

It is necessary to get the normals just right.

 

↓I created an example where the normals were adjusted by recalculating them in MODELER and then LT converted.

The one with the normal set to 18 produced the cleanest results.

 

18 seems like a fairly low value, but the one at the bottom right in particular looks good as it doesn't produce lines on curved surfaces.

 

If you set the value to suit your object, I think you can increase the detection accuracy and pick up minor irregularities while preventing unnecessary lines from appearing on curved surfaces.

 

 

About "Adjust accuracy based on scene size"

Even with normal 18, if "Adjust accuracy by scene size" is on, unnecessary lines appear.

However, with normal as is and normal 180, it picks up the lines you want to display in the concave parts more faintly than with it off.

It cannot be said that simply turning it off is better.

 

The two figures below are examples with "Adjust accuracy by scene size" on, but all the LT conversion settings are the same, except for whether to display small and large objects.

However, unnecessary lines appear when only the medium-sized object in the middle is displayed and LT converted.

The size of the scene has nothing to do with the proximity or distance of the camera or the size of the object. Or, in addition, the area where the object is displayed is defined as the size of the scene, as shown in the red frame in the image below, and the line drawing is adjusted taking that into account.

 

If that's the case, it makes sense that there was a difference in the line drawing even though there was no difference in the LT conversion settings.

As for "Adjust accuracy based on scene size," the above is just a guess, and I'm not really sure what criteria cause lines to be picked up well or to become faint or disappear, but I think it's good that the lines don't become too uniform.

 

So I keep "Adjust accuracy based on scene size" on all the time, and turn it off if I notice any problems, such as extra lines appearing.

 

 

Problems with adjusting normals

Sometimes adjusting normals alone is not enough.

With the curtain material I created previously, LT conversion did not work well unless the detection accuracy was around 60.

If there is a complex curved surface, even if you adjust the normal to 180, unnecessary lines may appear unless you lower the detection accuracy.

I think it's because the original shape does not become smooth enough.

I would like to verify and improve this area when creating 3D materials in the future...

 

And sometimes it's difficult to adjust the normals in the first place.

 

 

Freeze

First of all, when the object is complex and heavy, it freezes.

This is due to the lack of power in my working environment, but because of this, there are times when recalculating normals cannot be performed in the first place.

I try to deal with cases like the object with curved surfaces and bumps that I gave as an example earlier, but with the current file export method, the LT conversion usually comes out pretty nicely, so I usually leave the normal settings loaded.

 

 

Materials are shuffled

I don't know if it's my working environment or something, but when I recalculate normals the materials get shuffled.

↓If you recalculate the normals...

The materials have been swapped.

Why... Really... why...

You might think that if you recalculate the normals once, the materials will be shuffled again and returned to the original state, but they will not be shuffled after the first time.

Why...

 

If it's just the colors that have been swapped, you can just correct the color information, but if the color and texture image have been swapped, it's very problematic.

In the example, even if you want to replace the square tile image in the light blue area, there are fundamentally different specifications for things colored with color information and things that have a texture image applied.

Things colored with color information can only have color information inserted, so you cannot replace the texture image.

I don't know why they are shuffled...

If you are working in a similar environment to me and in the same situation, you may not be able to adjust the normal settings in the first place.

If there is a material for which it is difficult to draw clean lines, please forgive me as there may be various reasons for this...

 

For this reason, the way lines are drawn changes depending on the normal settings and the detection accuracy values during LT conversion.

I think the shape of the object also has an effect on this.

 

 

How to deal with materials that have different optimal detection accuracy values

For downloaded materials, you may have no choice but to deal with it depending on the detection accuracy.

The description of the material may include an example image of LT conversion.

If there is a description of the detection accuracy, it is a good idea to check it.

It is likely that the material will be converted to LT the best value.

 

If you want to perform LT conversion when combining materials with the best detection accuracy of 100 and 50, or if one material has parts that look better with higher detection accuracy and parts that look better with lower detection accuracy, I think it would be a good idea to try LT conversion twice, once with higher detection accuracy and once with lower detection accuracy.

I think it would be a good idea to create two types of line art and select the area to use partially.

In the image above, even with a detection accuracy of 60, the curtain part is not completely clean...

There are fewer unnecessary lines compared to 95, and this is just an example, so please forgive me...

 

After preparing two line drawing layers, roughly select the curtain part.

 

 

Invert the selection and create a layer mask on the line art layer with the extra lines.

The extra lines on the curtain have been reduced, and the areas where lines had disappeared at 60 have been resolved.

I think the amount of work required to add and correct the lines on the curtain will be less than with version 95.

Verifying normal settings

This is just a little extra that will not affect those who normally use 3D materials.

Please skip this part.

This is mostly a memo for myself.

 

The normals looked different depending on how you exported the file from the 3D production software to load into MODELER.

 

I wanted to verify this, so I created materials in several patterns as an experiment and posted the results of LT conversion with different detection accuracy.

This may be of some help to material creators.

 

・Two patterns, 1 and 2, with different file export methods in the 3D production software (different file extensions as well)

 

・Two patterns with extreme normal settings of 0 and 180 in the 3D production software

 

・Three patterns with normals set to "as is" without recalculating them in MODELER, and 0 and 180

 

The above are the 12 different 3D materials that were converted to LT.

I changed the detection accuracy for LT conversion to produce 3 to 4 patterns.

↓Table 1_1

↓Table 1_2

↓Table 2_1

↓Table 2_2

In file export method 1, the normal settings in the 3D production software do not seem to affect the line art, and the line art in Table 1-1 and 1-2 were exactly the same.

I thought 2 would be the same, but the only difference was the pattern of 180 degrees → 180.

Except for 2_Normal 180 → 180, the normal settings in the 3D production software had no effect in either 1 or 2.

 

In 2, even when I recalculated the normals in MODELER, all the line art results were the same except for 2_Normal 180 → 180.

By the way, the normals in 1 and 2 were the same.

 

The normal settings in the 3D production software have no effect, and depending on the file export method, recalculating the normals seems to be almost meaningless.

In my working environment, though...

File export method 2 was not compatible with creating 3D materials for Clip Studio Paint.

 

When setting up a 3D object in MODELER, I think it's a good idea to consider how to export the file.

I had a hard time using the output from method 2 for a while...

summary

This is a long post, but to summarize it briefly, it is as follows.

 

  • If you value smooth operation, use jerky materials

→ Be careful, you will need to fix the jerky when converting to LT

 

  • If you don't want to bother with retouching, use smooth materials

→ It may slow down the operation


・It is possible that the image was rendered using 3D production software, so please check the operation screen and LT conversion images in Clip Studio Paint.


When adding or modifying something that has been converted using LT

 

・Use smooth

 

・Adjust the control points

 

・Understand how much editing or modification is required

→Can it be done with smooth or control points?

→Check whether there is texture and how easy it is to add to it

 

For materials with different best detection accuracy values, prepare two line drawings, one with high detection accuracy and one with low detection accuracy, and use them partially

 

 

The End

The above are the things that are likely to affect line art when selecting 3D materials.

While I say how to choose, I've also touched on LT conversion quite a bit...

 

Thank you for reading this long post.

I think what people look for in 3D materials is different for each person, so I hope you can find the criteria for choosing materials that suit you.

 

For now I've only summarized line art this time, but I would like to make a version about tones as well.

I've mostly written the text, but preparing images and other things is a lot of work, so I think it will be a while before I publish it...

It will be even longer than this time, but I think I will be able to make suggestions on choosing materials to match your style.

I'm not sure if there will be demand for this content, though...

 

↓ I'm working hard to create the 3D materials while experimenting and thinking about various things, so if it seems like it will fit your requirements, please use it.

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