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Marianne Little

Is the LOD good enough?

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I am trying to make something with good LOD. I struggle with a building, but then I decided that I should upload something small to try on. Like a porch pillar. After a lot of cursing, the left one, the first from the left, is what I got so far.

I can not upload a super big image, but I cut out the pillars to show it better, and the image from a distance is how the pillar is visible all the way top to bottom.

I use LOD 1 in Firestorm.

LOD porch post_007.jpg

LOD porch post_007small.png

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Posted (edited)

And here. It looks like a stick, but it is there, straight from bottom to top. The middle porch pillar is where I took the first images. Still LOD 1.

 

 

LOD porch post_010.jpg

Edited by Marianne Little
added lod

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Not saying that this is  right or wrong but for something like the object here I would tend to do the following:

for medium LOD remove all the horizontal surfaces, a few meters away when it drops to Medium those are too small to warrant inclusion. You need to be the judge of what can and can't be removed but be ruthless.

for Low LOD, I'd drop to a single column, and have a fight with myself over whether it should be the thickness of the base and cap or the pillar, and probably settle on the pillar. In an object this simple though I'd probably decide I didn't care so much and leave the low and the medium as the same 24 triangle object.

for the lowest LOD an 8 triangle box is going to be fine, but you could go the whole hog and use the 8 triangles in a cross (when seen from above) and then use an imposter texture, use the LOW/MED as the model for the imposter  though so that the lowest is not showing detail that was not present in the preceding LOD. honestly though, making the viewer download a texture no matter how small, and carrying the extra triangle in the other LODs to support it, in this specific case is not (in my opinion) the right trade off and just go with the box.

 

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46 minutes ago, Beq Janus said:

for medium LOD remove all the horizontal surfaces, a few meters away when it drops to Medium those are too small to warrant inclusion. You need to be the judge of what can and can't be removed but be ruthless

You could probably remove the narrow lower protrusion close to the top too. That would reduce the triangle count to just 24 for the mid model.

 

48 minutes ago, Beq Janus said:

for the lowest LOD an 8 triangle box is going to be fine

More likely nine triangles, Beq's box with the width of the main part of the column and a single horizontal triangle to define the dimensions of the crown and base.

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3 hours ago, ChinRey said:

More likely nine triangles, Beq's box with the width of the main part of the column and a single horizontal triangle to define the dimensions of the crown and base.

Yeah I think the lod swap will be a lot less obvious if the final "tube" remains the size of the inner collumn.

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1 hour ago, Kyrah Abattoir said:

Yeah I think the lod swap will be a lot less obvious if the final "tube" remains the size of the inner collumn.

The LoD swaps shouldn't be noticeable at all actually.

It's possible to get the trinagle count for the lowest LoD down to seven by making the model triangular but in this case it's not worth it. Once you get below 10-12 triangles for a model there isn't anything to gain by reducing it further. So, assuming the top and bottom of the column are open:

  • Hgh Lod: 20 tris, 80 vertices
  • Mid LoD: 24 or 32 tris, 36 or 48 vertices
  • Low LoD: 9 tris, 19 vertices
  • Lowest LoD: Use LoD above

This is a very good example of the advantages of manually made LoD models btw. It's so easy to see how much better they are both when it comes to looks and performance.

 

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Very helpful. ❤️

I am looking at the tower I am working with, and making a custom led for it will be painful because I have already put in bevel edges and all that nice detail.

So the best thing is to make the tower basic shape, and use it for the LOD model?

Then throw in bevel edges and other things that create edges? Is that how you do it?

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3 hours ago, Marianne Little said:

So the best thing is to make the tower basic shape, and use it for the LOD model?

Then throw in bevel edges and other things that create edges? Is that how you do it?

It's one way to do it, and certainly not a bad way. The Medium LOD is typically the one that is visible to most of the people most of the time, as such it is worth making sure you get it right. 

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Continue to work on the tower.

The first images is LoD 1 in Firestorm. 1792033574_lodcollage.thumb.png.f502fb97e5482f9c27a67abaf302cfd4.png

 

The second is increased to LoD 2.

As you can see, I don't have a graphic quality that impress someone. Today I was working on a laptop that's not new or meant for games. I am as far away as 240 M with LoD 2. At least I can see something there. The shape is visible and it is not just a strange triangle. I wonder if I shall say it's good enough for my use.... It is not so bad that I should sit in a corner?

1210861981_lod1collage.thumb.png.67be8ad428888b2dea9271146f7d38d6.png

 

I have a new problem now, maybe I have to make the roof separate with its own LoD layer and upload it, then link it in SL. Or perhaps I can try and set a roof on the LoD model I have.

I am not sure what I am doing. I am just building freely, trying this and that.

 

 

tower.jpg

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14 minutes ago, Bitsy Buccaneer said:

You can definitely join the roof and the tower in Blender before you export.

If you have them made as two separate Blender files, import one file into the other. Then select both in Object Mode and Join.

 

To Marianne: 

 

Before joining two  objects that have come from SEPARATE FILES (just in case that IS the case) you need to make SURE that they both have the same exact UV map name.  If you do not you will loose the UVmapping on one (or more than one if you are joining several files).  The default UVmap name is "UVmap".  The imported one in my example (no textures) is NOT called that. So joining these two meshes together would result in losing one of the UVmaps.    To fix this issue, click on the "+" sign to the right of the UVmap name and add a NEW UVMAP. This will be named "UVmap" hence the map names will be identical. 

 

CHOOSE that map by clicking on the correct name. I always delete the map I will NOT be using for neatness.   THEN you can join.  It will be very obvious that you have a problem if you are in material view; some materials will no longer be visible. 

 

You will likely see this most often when you export prims into a DAE file.  Most other times it won't be a problem until you start doing some really tricky stuff :D.   Also it is good to make sure you have removed any duplicate vertices. [Edit mode > select the mesh > W_key > remove doubles (again this is in 2.79 so you may need to look for the "remove doubles" in 2.8).

 

It gets a little more complex than this but that's the basic idea. Took me for-e-ver to work this out.  The names can be anything by the way as long as they are identical to each other.  This is true in Blender 2.79 and below. It seems unlike that has changed in 2.8 but if so, someone will add that info.  

image.thumb.png.c11123c3a5791ea02dfb226782b669f2.png

 

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45 minutes ago, Bitsy Buccaneer said:

You can definitely join the roof and the tower in Blender before you export.

You can but it's generally not a good idea. It's a common mistake to try to put too much into a single mesh. Merging meshes will nearly always increase the downlaod weight considerably and also limit the options for optimising LoD.

Some may believe that one big mesh is less render heavy than several smaller ones but that is only true if you merge faces too (since each face is handled with a separate draw call anyway) and even then it has to be weighed against the disadvantage of less optimal LoD models.

When it comes to minimizing land impact, ideally you want the average download weight of the parts of a linkset to be slightly higher than 0.5. That's not always possible of course but the closer you can get, the better.

For buildings and other outdoors structures there is a third reason why can be a good idea to split: draw distance. The cutout distance for each part in a linkset is determined from its center and since you want the wall facing you to be the first to appear and last to vanish, it can be a good idea to make each outside wall a separate mesh. This doesn't matter for a small building like this but for large houses it can very significant.

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An update.I decided to speed up the process and buy a roof. I got a cheap one from Rhodan builds, and when I placed it in a sandbox and was flying away, it held the shape well.

I have started on the base, the one that's pushed through the roof and is holding up the octagon room. I use a cylinder with fill "nothing". And 8 vertices, so it's an empty octagon "tube". I am working on edge loops and extrude for the details, but I will not/ need not go overboard with details. The Linden house does not have so many details.

For this, I have saved only the octagon tube for the LoD file, before I did anything more. I mean to use it as the physics model too. That's correct?

I have to work on the UV editing, and I am using three different tutorials. Two I have bought, and one free from Olde Tinkerer, that I managed to follow once before. https://oldetinkererstudio.com/lets-create-archery-tower-game-asset-blender-2-8-tutorial/

This time though, I am somehow stuck at the end. This UV work does not agree with me. It is so many small steps, and all has to be followed 100%. It does not help that I am sitting here with the laptop now. It has a small screen. I can feel the need to get it over with, I have spent much time on it already. I know it is because I have no practice, but I have to finish it before I am so tired that I stop working on it.

Maybe I have something to show in a few days. I hope so.

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Hi Marion :)

Just a note: I have just watched the video tutorial you linked to and thought I should just warn you that using the Smart UV Unwrap is ok for that particular model But it is not what you should be using if you  intend to use wood textures,  and clapboard textures and tile roof textures on your tower model in SL.

When using pre-made textures like that then the UV unwrapped Islands need to "fit" the  texture. For example all the wood textures islands should be layed out horizontally so that they are aligned with the grain of the wood on the texture. Same with the UV islands for the roof tile texture ..............

To have that control you need to mark the seams by hand and then edit (position, rotate, scale) the unwrapped islands in the UV space.

But perhaps ypu knew that already :)

There is a "trick" you could use that would parhaps save you some time with UV unwrapping and editing.

1: Create your Octagon building.

2: Delete 7 of the sides. 😮

3: Mark seams on the remaining side.

4: Unwrap and edit all the islands for that one side.

5: Add an Array modifier using rotation about the center  to recreate the 7 deleted sides. The result of  this is the UV's of the 7 new sides will use the UV's you layed out for the original side.

Now it is way to late for me to explain this method in more detail but I will try to post something for you tomorrow afternoon.

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Posted (edited)
10 hours ago, Aquila Kytori said:

Hi Marion :)

Just a note: I have just watched the video tutorial you linked to and thought I should just warn you that using the Smart UV Unwrap is ok for that particular model But it is not what you should be using if you  intend to use wood textures,  and clapboard textures and tile roof textures on your tower model in SL.

When using pre-made textures like that then the UV unwrapped Islands need to "fit" the  texture. For example all the wood textures islands should be layed out horizontally so that they are aligned with the grain of the wood on the texture. Same with the UV islands for the roof tile texture ..............

To have that control you need to mark the seams by hand and then edit (position, rotate, scale) the unwrapped islands in the UV space.

But perhaps ypu knew that already :)

There is a "trick" you could use that would parhaps save you some time with UV unwrapping and editing.

1: Create your Octagon building.

2: Delete 7 of the sides. 😮

3: Mark seams on the remaining side.

4: Unwrap and edit all the islands for that one side.

5: Add an Array modifier using rotation about the center  to recreate the 7 deleted sides. The result of  this is the UV's of the 7 new sides will use the UV's you layed out for the original side.

Now it is way to late for me to explain this method in more detail but I will try to post something for you tomorrow afternoon.

The last trick is SO promising! It will perhaps work best if I remake the octagon house part to be 8 walls with 8 windows, instead of 5 walls with windows, one with a small round window, two solid walls? Maybe I am too ambitious by making different walls.

And I would want the panel siding texture parts to be drag and drop inworld. So I can change panel on the Linden home, and don't have to remake an UV each time.

The left tower is built by prims inworld, saved as Collada, imported to Blender and select all + join. It has many small errors close up, and fall apart already 40 - 50 m away. The right is my blender build. Note that the roof and windows in both isn't built by me. I am trying different windows to find some with good enough LI.

I managed to do something with the UV, but every part is drag and drop. I did a solution of the white wood trim, by using different colors on horisontal and vertical wood. Since we can import 8 textures to SL. It looks a bit better because of that.

lod1_001.jpg

Edited by Marianne Little
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Ah yeah sometimes it's a good idea to think ahead in terms of unwrapping as it can save you time and also texture count/size.

The typical workflow places unwrapping after modeling but you can absolutely do both at the same times. To make things like hair and fur it's actually recommended because sometimes the textures should adapt to the UVs,  while in other cases the UVs should adapt to the textures.

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Posted (edited)
11 hours ago, Marianne Little said:

And I would want the panel siding texture parts to be drag and drop inworld. So I can change panel on the Linden home, and don't have to remake an UV each time. 

The UV's will be layed out by material layer so that when you select that material face in SL to apply your texture you will be selecting that particular UV layer.

As you already mentioned a model can have only one UV map but up to 8 materials. These materials can all be laid out onto a single "layer" , each on its own layer, or laid out so some have there own layer and others share a layer.

22 hours ago, Aquila Kytori said:

There is a "trick" you could use that would parhaps save you some time with UV unwrapping and editing.

1: Create your Octagon building.

2: Delete 7 of the sides. 😮

3: Mark seams on the remaining side.

4: Unwrap and edit all the islands for that one side.

5: Add an Array modifier using rotation about the center  to recreate the 7 deleted sides. The result of  this is the UV's of the 7 new sides will use the UV's you layed out for the original side.

1: The octagon  to be UV unwrapped :

Note: the Octagon building in this example has 5 different materials assigned to it. Wood, Inside panels, Roof, Floor, and Panel sidings. All but the Inside panels will have their UV's laid out for pre_made textures. Inside panels will just be tinted.

689671947_1OctagonUV-min.thumb.png.f5ba9746217d82e029930bc2c87b8630.png

2:  Isolating 1 of the sides and deleting the 7 others:

  Assigning seams to the outer edges of one of the side will make it simpler to select only this side later on.

1273391745_2OctagonUV-min.thumb.png.c9fb913301abc31b1839ee4d393a9838.png

The outer edge seams need to be added to the edges on the inside of the model as well :

1017551882_3OctagonUV-min.thumb.png.d2cf31435df339ad7ef92f8030302c44.png

With these water tight seams in place we can now select this one side.

In Face select mode and with the mouse cursor over one of the faces of this side hit the L key. The complete side and only this side should now be selected. If all the model is selected then the seams are not water tight. you will have to go back and find  and fix the leak:

312207733_4OctagonUV-min.thumb.png.2ff88c42a313341d6979e4aba94c21e7.png

Next we need to Invert the selection using the keyboard shortcut Ctrl + I    ( or choose Invert from the Select menu )

1350715177_5OctagonUV-min.thumb.png.77c6d4098fd2b7f95f640d5954c5a80e.png

Delete the selected faces.

3: Add Seams to the appropriate edges of this side in preparation for UV unwrapping:

1537965426_6OctagonUV-min.thumb.png.16f01f122b36104735dcbf6306795f50.png

With all the seams in place we are ready to unwrap:

1770157100_7OctagonUV.thumb.png.7f5c7a72c76c4791cec884badcfa4181.png

4: Editing the UV islands,

First separate them by material.

Then select each material one by one and arrange them onto the UV space.

In the following screenshot all the "white wood" material UV islands have been scaled up some and arranged. Because a pre-made texture will be used overlapping the islands is not a problem.

(Note:If we were intending to bake out a texture then a little space would have to be left between islands.)

The inside panels will not be using a texture. They are intended to just be tinted from the SL build floater so the size and position of these islands is not important. They have their own material assigned to them but can share the same layer as the wood UV's.

1788808985_8OctagonUV.thumb.png.a5a2387670be88113c383566544a8231.png

The other three materials, "Roof" , "Panel sidings" and the "Floor" each have been scaled up and given their own "layer".

767306840_9OctagonUV.thumb.png.1008d1845acde3429c07db9fc4005333.png

 The combined UV space with the complete side selected :

130942900_10OctagonUV.thumb.png.abd048d87346166fac2b7221475c6283.png

 

5:  Using an array modifier to recreate the missing 7 sides :

An Empty is added to the center of the octagon  and an Array modifier is used  to create new faces and rotate them around this Empty.

for more info see this tutorial by Jonathan Williamson  .   https://www.youtube.com/watch?v=s5teWMHUDgs Its  version 2.7 but the controls are still the same in 2.80.

1984583022_11OctagonUV-min.thumb.png.5de28ed0f40cc4be3ca564fa6717b571.png

In the array modifier Increase the Count to 8 :

572164218_12OctagonUV-min.thumb.png.a624f19c530cfa9383ae4ac652bbba4f.png

 

smallgif.gif.de73b05aa20e9ff6f57490e182b45a47.gif

 

When ready, in Object mode Apply the modifier. and  just to be  sure ..........remove doubles:  Vertex > Merge Vertices > By Distance.

Now all 8 sides are UV unwrapped.  Each of the original UV islands will have 7 copies stacked above it.

 

11 hours ago, Marianne Little said:

The last trick is SO promising! It will perhaps work best if I remake the octagon house part to be 8 walls with 8 windows, instead of 5 walls with windows, one with a small round window, two solid walls? Maybe I am too ambitious by making different walls.

To create the  sides with the blank walls (and side with round window) just delete the unnecessary geometry window openings from the relevant sides. Fill in the blank spaces and assign then the relevant material.  Select the new faces,  unwrap and edit so that they are at the same scale etc as the other islands using the same material.

 

 

 

Edited by Aquila Kytori
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