Blender for Beginners

[Fidcal]

Our own wiki says to set Spacing to 10 and this matches Dark Radiant's grid size of 1. But these units seem to be doom units anyway so setting the grid to 10 is like setting Dark Radiant to 10.

 

I can make no sense of it. How am I to work with this?

[Fidcal]

OK, taking a fresh approach to this. Blender units, Doom units, any game units have no particular 'size'. Doom units derive their 'meaning' simply from previously created assets such as doors, AI, crates.

 

So if I make a crate of 32 x 32 x 32 in Blender it's just a block that is 32 x 32 x 32. That is, a file is created with the equivalent of the numbers 32 x 32 x 32. There are no 'units. If I load that into Doom3 then those numbers are automatically 32 x 32 x 32 doom units. If I load it into Oblivion or Assassin's Creed or Thief then likewise the same applies. So if Oblivion crates are normally about 8 x 8 x 8 then this crate will be bigger in that game.

 

Alright, so simplified, Blender units are Doom units for our purposes. So the grid unit can be anything the user wants. So it makes sense to me to make the small grid 8 and the larger grid 64.

[Fidcal]

Another session, more trial and error. Seems to me that:

 

Spacing: the basic grid unit. Set at 1 for 1 doom unit. The larger grid is fixed at 10 x 10 of these units.

 

Lines: Mysterious. Seems to enlarge grid but why not just have a full grid in the first place?

 

Divisions: No idea. I thought it changed something before but now I can see no effect. Possibly invisible steps for grid snapping? I'll have to test that.

 

Adjusting any of the above is tortuous compared to Dark Radiant. It is a super fine mouse drag which so sensitive it is very difficult to get precisely what you want.

[Fidcal]

Posted on a Blender forum and got an explanation. First, the grid size changes between perspective and ortho. If you set spacing to 8 and divisions to 8 then in Ortho you get a big grid of 8 x 8 and a small grid of 8 x 8 as you would expect. But if you then switch to perspective view there is only a fixed, unchangeable grid of 10 x 10 and no smaller grid. I don't even want to ask why. <sigh> Add to that, the contrast between these lines is so faint I often cannot see them at all. All I can think of is to set it to 10 x 10 x 10 in ortho then at least it will match perspective view albeit without the smaller grid. Then fiddle some more with grid color, background color, and screen res to see if I can make it clearer.

[Fidcal]

Day 6: Next effort I've got the seat height set at 24 units high in Blender and it's exported to Dark Radiant with that same height. This is not yet properly wrapped. As I suspected, the two big cross cuts in the tutorial were completely unnecessary and confusing and I did it without them this time.

 

[Fidcal]

Do we have any general preference as to where the origin should go in Dark Mod? Not sure it matters with a chair but some objects such as the rotary control, lever, doors, etc need the origin at the point of rotation. I'll search the net to see if I can find how to move the origin anyway and probably move it to the centre floor.

[Mortem Desino]

Generally, our origins for furniture are way at the bottom of the visible mesh or (if applicable) the collision model, so it's easy for mappers to drag them to the floor. Same goes for movables so that they don't begin the map by clipping into worldspawn and cause fun physics issues.

 

The grabber behavior won't change if an origin does, because the code doesn't look for the origin of a moveable, it actually calculates the center of mass.

[Fidcal]

Thanks MD; I'll aim for that when I figure out how to move the origin.

 

Meanwhile, I'm finding the compass texture is an ideal test texture while I'm trying to understand wrapping. It has a clear square black panel and a distinct image and even a pointer so I can see a common direction when I find out how to rotate.

 

[Fidcal]

Day 8: Not given up on this yet but have made no progress even though I am having several sessions a day with Blender still. I've restarted the chair tutorial for the third time but determined to get to understand the dimensions which I find very confusing. I made a block 6 x 2 x 1 but for some reason the edge lengths show it as a cube 9.290 x 9.290 x 9.290.

 

[rich_is_bored]

I'm not sure what is the cause of all your troubles. I just did a scale test in both 2.49 and 2.5 without issue.

 

I exported an 8x8x8 brush as an obj. Then I imported it into Blender. Then I set the spacing and divisions of the grid to 8. This results in a grid where major lines are 8 Radiant units apart while minor lines are 1 unit apart. And edge lengths are reported the correct length.

 

Here's the blend file if you'd like to see for yourself. Perhaps you can compare it with your own work and spot the discrepancy.

 

scaletest.blend

[Fidcal]

Thanks, I'll check that later. Though I am wondering why you made a block in DR and transferred it instead of making it in Blender in the first place.

[Fidcal]

OK I see that but observe some interesting things. I see a diagonal length too which I don't normally. Then I realize this object is a 'mesh' and not a 'cube'. I hadn't realized there was any difference. I thought a cube was just a quick default way to get a mesh shaped into a cube.

 

So to compare I create a cube. Normally this will be 2 x 2 x 2 by default. In your settings it is 16.001 x 16.001 x 16.001 (another example of inaccuracy which bugs me) but why not 2 x 2 x 2? But wait, then I realize it is rotated relative to the grid. Maybe because I happened to have the grid view rotated when I created it - only ever made a cube from top view before probably and never noticed. So to create a new cube one has to remember to make sure one is perpendicular in view? But it is still 16.001 x 16.001 x 16.001. Let's see if I can set it to 16 x 16 x 16:

 

I can't select it. I've been using Blender for hours every day for 8 days and I don't even know how to select an object. I right click it. Nothing. I press A to deselect A and repeat and it selects all objects, A again to deselect. Now right click one object. Nothing.

 

Maybe I have to be in object mode. Change to object mode. Right click a cube. Not clear with these colours but I think I selected the cube. Ah! I see all these cubes I've made and the original mesh are all one 'object' and I can't select any one of them individually. Well, not by the normal method anyway. This is what hampers me. Every little thing I try I find I hit up against something else I have to go away and research to proceed.

 

What I wanted to demonstrate was, if you make a 'cube' 6 x 2 x 1 then try to enlarge it it 7 x 2 x 1 you can't because it increments in some fraction of 6 so you would end up with something like 5.986 x 2 x 1. Leastways, other tests have come out that way but I can't do it because I can't make a 6 x 2 x 1 cube.

 

OK, maybe the whole problem is something to do with the difference between meshes and cubes. But the only tutorial I am working with is using a cube. And after all, a cube is the default in Blender. I know nothing else yet. I have not even progressed to meshes. Perhaps their dimensions are calculated differently. Maybe if I work with meshes all my troubles will be over. But the tutorial is for a cube.

[Fidcal]

I can't find an answer to this so I'll ask on both forums:

 

What is the difference between a cube and a mesh? When would you use one rather than the other?

[Fidcal]

Except that blenderartists.org server is down.

 

Oh well, just twiddle my thumbs for another day....

[rich_is_bored]

I made the block in Radiant to serve as a scale reference for adjusting the grid size in Blender. The only attribute of interest should be the scale. Any other peculiarities you've noticed about the mesh are simple modeling misconceptions you'll dispel as you gain experience.

 

Rest assured that there is no difference between a cube and a mesh. It's all vertices and faces. The cube I imported from Radiant was triangulated. In other words, it's composed entirely of 3 sided polygons, otherwise known as tris. It's worth mentioning that most games only support the use of tris.

 

The reason why you see a diagonal line running across each of the six sides of the cube is because it's just not possible to make a 4 sided face with a single 3 sided polygon. If it helps, think of it in 2 dimensions. You can't draw a square with a triangle but you can draw a square with 2 triangles.

 

Now you're probably wondering why you don't see tris on a cube constructed within Blender and it's simple. The two tris that comprise each side of a cube are represented as a 4 sided polygon called a quad. The tris are technically there but for artistic purposes they aren't represented that way unless you explicitly triangulate a quad, n-sided polygon, or entire mesh.

 

You can verify this by creating a plane in object mode in the top down view port, entering edit mode, selecting two opposing vertices, and moving them a considerable distance along the z axis. When you rotate around the plane to view it at different angles you'll notice a sharp bend along the diagonal.

 

Congratulations. You've just created a non-planar surface. It's impossible to create such a surface with triangles and that's precisely why everything is represented as tris internally. Triangles are the only forms that allow for a surface to remain flat regardless how the vertices are positioned.

 

But enough of the modeling fundamentals. Here's some Blender specifics. Forgive me if this isn't as well thought out as the rest of my post. I've spent quite a bit of time on this already.

 

Only the circle, uvsphere, icosphere, cylinder, cone, and torus allow you to define the scale of the object prior to placement. The cube will always start at 2x2x2. Read on for why the edge length might report otherwise. In 2.5 you can adjust the dimensions of the cube with the utmost precision using the properties panel.

 

In version 2.5 they have added a "align to view" option when adding primitives to the scene. This would avoid the rotated placement issue you had but then so would placing primitives in top, side, or front view.

 

When you create an primitive in object mode, the object is named accordingly. Create a cube and the object will be named cube. You can select the cube object, switch to edit mode, delete the cube mesh, add a sphere mesh, and the object will still be named cube. The object in the blend file linked above is named mesh because it was an imported mesh. You can rename an object in the object panel (shortcut: F7).

 

Objects and meshes are two different things. Objects are containers. Meshes are data stored within those containers.

 

Objects are manipulated in object mode. Meshes are manipulated in edit mode. If you perform an operation to an object, it's only applied to the object. The mesh maintains it's own local coordinate system. If you scale the object down, and the mesh up, the edge length reported will be wrong only because it's reporting values relative to the local coordinates. If you apply any transformations performed to the object, the edge length reported will be correct.

 

In versions prior to 2.5 snapping to the grid is a separate operation. You scale something close to where you want it and then click mesh > snap > selection -> grid. In 2.5 snapping to the grid is a toggle that applies to all operations.

Edited March 4, 2010 by rich_is_bored

[LordZ]

Hello.

I am modeler of Hexen: Edge of Chaos. I am only one in our team who use blender3D and I've noticed Fidcal having hard time understanding some of blender's usage. I would be glad to offer my help if you need some advice regarding blender -> doom3 process to .ase.

 

I use .ase for many reasons, every other application can import it almost without any problems, blender can import it without any problems. .ase can be edited with just text editor if you forget to do something. Blender has some issues with smoothing when exporting to .lwo. Importing .lwo works with some models, I yet need to figure out what causes problems with some models.

 

 

I didn't read every post so I'm not sure if you have managed to solve this next problem

 

Day 8: Not given up on this yet but have made no progress even though I am having several sessions a day with Blender still. I've restarted the chair tutorial for the third time but determined to get to understand the dimensions which I find very confusing. I made a block 6 x 2 x 1 but for some reason the edge lengths show it as a cube 9.290 x 9.290 x 9.290.

 

 

This is simply caused because when you made cube, you scaled it when you were in object mode, always do all editing in edit mode.

 

To fix this, just go to object mode, select your mesh, press CTRL+A, apply scale. Now go to edit mode and you should be set.

[Springheel]

Oh well, just twiddle my thumbs for another day....

 

Or you could try LW instead.

[Fidcal]

Yes, I have been dabbling in Lightwave today and dragged out and resized a cube much like I'd do in Dark Radiant so that felt more intuitive. I'd like to at least get the basics of both programs.

 

Thanks for all replies which I've read but will need to study further. In particular the revelation that there is a manual snap to grid. Woohoo! For the first time I managed to grid snap my friggin' model so I have front legs that match the back legs of my chair. Nothing I've read so far has bothered to mention that you have to manually grid snap! I expected by default that it would snap to grid instead of jumping in steps that make no sense to me.

[Serpentine]

Blender has some issues with smoothing when exporting to .lwo. Importing .lwo works with some models, I yet need to figure out what causes problems with some models.

, thanks!

[Tels]

This is simply caused because when you made cube, you scaled it when you were in object mode, always do all editing in edit mode.

 

To fix this, just go to object mode, select your mesh, press CTRL+A, apply scale. Now go to edit mode and you should be set.

 

Uh, is there a reason this is so confusing and complicating (whats the difference between "edit mode" and "object mode", anyway?)

[Fidcal]

I suspect part of the complexity is that Blender is an indepedent, stand-alone erm... display (I won't call it a game) with its own material properties, multiple objects scenes, animations and probably sounds etc whereas all I want is a single object to export with no material properties or texture which I add later.

 

Anyway...

 

Stuck again at the unwrap stage.

 

I renamed material to test

I renamed texture to test

I assigned one of the internal images: stucci

Also because I have renamed the object from cube to chair if I saw the word cube in the materials or texture panel I changed it to chair.

 

Edit mode, chair selected

U - unwrap and the square in the uv editor goes pink. So far so good.

 

Now to assign an image to it. The tutorial then says to select an image and his image shows a button something like a map pin icon with a selector at the side. This is just no present in my uv editor bar. I can see where it is in his screenshot but it is not in mine. (I must have done this before when I first did this tutorial but how I do not know.)

 

So I go back to the materials buttons then the texture buttons to see if I've done something wrong. I see something about linking to the object so maybe I've just created a material but it is not assigned to my object. I click it and now most of the panels in the buttons area for both material and textures have all gone and I have no idea how to restore them. In 'textures' all I see is one panel headed Preview (but there is no preview any more.) In 'Material' all I see is an empty preview panel and Links and Pipeline. It may be that my changing cube to chair has caused all this problem and I should have left the whole damn thing as 'cube'.

 

OK, I abandon that as hopeless and reload an earlier save. Damn. Lost all the texture thing I set up and all the change of config. Problem is that all the config is saved with every save. That is, if you re-arrange the screen or change colours or adjust sizes, they are all lost when you load a previous save.

[Crispy]

Uh, is there a reason this is so confusing and complicating (whats the difference between "edit mode" and "object mode", anyway?)

Object mode manipulates whole objects, edit mode manipulates vertices / faces / edges.

 

It's the difference between scaling an object and just moving its vertices around. Every 3D modelling program I've used has the same concept, even if they present it slightly differently.

[Fidcal]

Back on track. This was actually the problem. In his tutorial page on uv unwrapping he doesn't tell you to set object mode at the start to choose the image. He assumes you still have object mode set from yesterday when you did the texturing part in the tutorial on texturing. You use edit mode to actually use the uv editor but object mode to enter an image for it.

[stumpy]

the general problem with tutorials is assuming that the person that is using the tutorial knows what you are talking about when in reality they dont, and most tutorials go confusing when steps to do things have been left out because assuming is the mother of all cockups.

[Fidcal]

Yeah we need a tutorial tutorial. But where you would learn how to write it?