Blender Questions and Answers (I hope)

Tralfaz

Hi folks,

A lot of discussion has been taking place in Hunter G's thread on the reboot of the Constitution. I would like to start a general thread here for questions and answers regarding Blender.

I've notice quite a few people using Blender and am quite impressed with what they have been able to model.

Once you have the model completed, what type of render capability does Blender have?

What is the quality of its internal renderer?

How efficient and fast is the renderer?

What external renderers can be used with Blender?

What file formats can Blender import and export?

Just a few questions for now.

Thanks in advance...
Al

McC

Tralfaz wrote: »

Once you have the model completed, what type of render capability does Blender have?

What is the quality of its internal renderer?

How efficient and fast is the renderer?

This isn't quite a clear-cut question, actually. Blender technically has two "internal" renderers.

The "old" renderer, which is no longer maintained, is "Blender Render" or "Blender Internal." It has okay quality and okay speed, but it shows its age pretty fast.

The "new" renderer, which is actively supported and developed, is Cycles. Cycles has outstanding quality (here are some tutorials on the Blender wiki, here's my current WiP thread -- everything in here was rendered in Cycles), but its speed is highly variable based on render settings, scene parameters, and -- most importantly -- hardware.

Cycles takes full advantage of the CUDA renderer architecture, which is currently only implemented by nVidia cards. The rendering can thus be done by your graphics card, rather than your processor, and go blazingly fast.

How fast? A render that took me a couple of hours on CPU took six minutes on GPU, with the exact same render settings. Same output quality, same lighting, same camera, mesh density, etc.

If you don't have an nVidia card, unfortunately, you can't take advantage of this. AMD card hardware architecture is radically different. There are experimental builds that are working on OpenCL support for Cycles, but they're not in the main Blender download yet.

More information about Cycles and GPU rendering here.

What external renderers can be used with Blender?

This one, I'm not sure about. Ever since they introduced Cycles, I've used nothing but. I know Yafaray used to be a big thing and Blender website still has links to external (open source!) renderers, so it seems like some kind of support still exists.

Between Cycles and the internal Compositor, though, you don't really need anything else.

What file formats can Blender import and export?

By default, the following.

Import:
Collada (DAE)
Motion Capture (BVH)
Scalable Vector Graphics (SVG)
Standford (PLY)
STL (STL)
3D Studio (3DS)
Autodesk FBX -- ASCII (FBX)
Wavefront (OBJ)
X3D Extensible 3D (X3D/WRL)

Export:
Collada (DAE)
Standford (PLY)
STL (STL)
3D Studio (3DS)
Autodesk FBX -- Binary (FBX)
Wavefront (OBJ)
X3D Extensible 3D (X3D/WRL)

(Yes, that's right, Blender can't import the FBX files it exports. :rolleyes: I imagine this is something that will change, in time.)

Many, many, many add-on scripts exist that greatly extend these lists, including one for LightWave Object (LWO).

There are a ton of addon scripts for Blender, many of which are crucial. Here's a tour of some of the ones I use most

spacefighter

blender has great render capability both for fast(ish) rendering and for very high quality slow rendering. it can also take third party rendering "plugins". internal is nice and quick, i use it al the time, so if you find some of my youtube vids you can see the sort of thing it did in the hands of a beginner, some of the later videos show what i do with internal these days. blender also contains cycles renderer, this comes within the program and you can switch between cycles and internal with the flick of a virtual button ( and some hassle altering the materials settings afterwards). cycles is slower and may give fireflies (which i have never seen in internal)but can do advanced raytracing and shaders, both internal and cycles can do simpler raytracing also including refraction through certain transparent materials. the frames of my videos on youtube took about 30 seconds each to render in 2000x1400 resolution, which was degraded upon youtube upload. blender has animation capability for simple keyframing, complex keyframing, physical modelling of processes in the graph editor (like realistic accelerations), and particle systems(fire,water,smoke,explosions) which can respond to force fields (gravity,electrical,magnetic,wind,other) and by contained with collisions. blenderguru http://www.blenderguru.com/ is a good place to get some pretty detailed blender tutorials, blenderartists http://blenderartists.org/forum/ is good for technical support. mcc has given a list of what blender will import by default but ticking a few boxes in user preferences opens up some new possibilities for imports and exports, be warned although it will import all those formats he has listed, and others you can turn on, it won't always import them well. lightwave models (lwo) have a habit of losing their material settings and texture mapping upon import, exporting to obj will lose some procedural textures and parenting,rigging,object origins, exporting to collada loses some material settings and procedural textures, , importing collada often lets the rigging,origins,parenting survive but can lose some material effects. blender can import fbx IF you find the right script lying around online, i know there is one.

MaxxRush

McC wrote: »

This isn't quite a clear-cut question, actually. Blender technically has two "internal" renderers.

The "old" renderer, which is no longer maintained, is "Blender Render" or "Blender Internal." It has okay quality and okay speed, but it shows its age pretty fast.

The "new" renderer, which is actively supported and developed, is Cycles. Cycles has outstanding quality (here are some tutorials on the Blender wiki, here's my current WiP thread -- everything in here was rendered in Cycles), but its speed is highly variable based on render settings, scene parameters, and -- most importantly -- hardware.

Cycles takes full advantage of the CUDA renderer architecture, which is currently only implemented by nVidia cards. The rendering can thus be done by your graphics card, rather than your processor, and go blazingly fast.

How fast? A render that took me a couple of hours on CPU took six minutes on GPU, with the exact same render settings. Same output quality, same lighting, same camera, mesh density, etc.

If you don't have an nVidia card, unfortunately, you can't take advantage of this. AMD card hardware architecture is radically different. There are experimental builds that are working on OpenCL support for Cycles, but they're not in the main Blender download yet.

More information about Cycles and GPU rendering here.


This one, I'm not sure about. Ever since they introduced Cycles, I've used nothing but. I know Yafaray used to be a big thing and Blender website still has links to external (open source!) renderers, so it seems like some kind of support still exists.

Between Cycles and the internal Compositor, though, you don't really need anything else.


By default, the following.

Import:
Collada (DAE)
Motion Capture (BVH)
Scalable Vector Graphics (SVG)
Standford (PLY)
STL (STL)
3D Studio (3DS)
Autodesk FBX -- ASCII (FBX)
Wavefront (OBJ)
X3D Extensible 3D (X3D/WRL)

Export:
Collada (DAE)
Standford (PLY)
STL (STL)
3D Studio (3DS)
Autodesk FBX -- Binary (FBX)
Wavefront (OBJ)
X3D Extensible 3D (X3D/WRL)

(Yes, that's right, Blender can't import the FBX files it exports. :rolleyes: I imagine this is something that will change, in time.)

Many, many, many add-on scripts exist that greatly extend these lists, including one for LightWave Object (LWO).

There are a ton of addon scripts for Blender, many of which are crucial. Here's a tour of some of the ones I use most

Okay... I just saw this thread for the first time last night, and I think it'll help me to learn more about Blender, except I can't seem to get good renders using Cycles.

First off, my specs:

Blender 2.69a
Win 7 Pro 64
AMD FX-8340 8-core processor
16GB DDR3 1800 RAM
Nvidia GeForce GTX 780Ti 3GB
2TB HDD

Up until now, I've been using the standard Blender renderer, and get results I'm happy with, although not to the standards of most people here (see my thread here: http://www.scifi-meshes.com/forums/showthread.php?80289-Honorverse-stuff ) I always render at 1920x1080 in PNG with RGBA for a transparent background so I can overlay the render with some premade backgrounds I use for posting my images.

For now, my settings match those of yours, McC, on your tips page(s), except my AO is at 1 and the Distance is 15. I've experimented with different AO settings and distances, and even turning it off completely, but nothing looks anything like the first render. I get nice smooth surfaces, but can't seem to get a good light/dark side and shadows. When I *do* get shadows, they're hard edged, almost like Toon Shader shadows, and don't shift smoothly from shadow to light on the curved surface of the hull.

I don't use any textures at all, and I've already figured out what I need to do for my emissive and reflective (chrome, gold tinting, running lights, Rolly ThingA? glows, etc.) materials. My lighting setup is a sun, and a single fill spotlight (very faint settings in Blender render - just light enough that my shadows aren't pure black) almost exactly opposite my sun, both vertically and horizontally.

If you could explain this to me in a way that I can understand, it would be appreciated. Treat me as if I'm a complete newbie to the software - please don't make the mistake of a lot of tutorials I've seen where they assume you already know something about what you want to do. I don't (at least, in regards to Cycles), and also I have a slight learning disability that makes it difficult for me to follow written directions, unless they are explicitly written out. OTOH, I *have* figured out where you get those fancy node images that I always see you posting, so if you say, "Go to the Node Editor," I've got that.

What I want is the effect/look on the left (Blender Render, about 17-20 minutes), and what I get is what's on the right (Cycles, a little over a minute). I also don't get a transparent background, even though I have PNG and RGBA selected:

McC

For now, my settings match those of yours, McC, on your tips page(s), except my AO is at 1 and the Distance is 15. I've experimented with different AO settings and distances, and even turning it off completely, but nothing looks anything like the first render.

As a first guess, I think you have your AO cranked up too high.

"AO" in Blender doesn't quite mean what one might expect. It's still definitely ambient occlusion, but by default the AO is added to the existing luminosity of the scene. Since AO only darkens in crevices and such, this generally results in super-illuminating the rest of the model.

There are a couple of ways to compensate for it. The first is to simply turn your AO "Factor" way down. 0.05 or so, to taste. This will include it, but make its impact greatly reduced. That should address your immediate over-blown lighting issue.

The better way to do it is with the Compositor.

• In the Render Layers tab, make sure 'AO' is ticked on in addition to 'Combined' and all the sub-options under Diffuse, Glossy, and Transmission. This will render out separate passes for each of these, that you can then combine. If you have emissive materials, also turn Emit on.
• "Combined", unfortunately, will automatically mix the AO pass, and so we can't actually use it, so we'll have to reconstruct it manually!
  • In the Node Editor, make sure you're in Compositing mode (the middle of the three mode buttons).
  • You want to hook your Direct and Indirect channels into your Color channels (for Diffuse, Glossy, and Transmission). To do this, create an Add node that uses Direct and Indirect as inputs, then a Multiply node that uses the Add node and the Color channel as inputs. You should end up with three of these -- one for Diffuse, one for Glossy, and one for Transmission. This "reconstructs" the basic Combined pass.
  • As an additional step, you next want to add another Multiple node with the AO and the Diffuse Multiply as inputs.
  • Now, you just need to Add all of these nodes together; order doesn't (at this point) matter. This is where you add the Emit node, if applicable.

Now when you render, the ultra-bright AO will serve only to darken the shadowed areas, while leaving the super-white areas unchanged from their other channels.

This is most definitely more complicated, but it also results in much better renders (IMO!)

Here's a screenshot of what my general render node setup looks like (click for full size):

When I *do* get shadows, they're hard edged, almost like Toon Shader shadows, and don't shift smoothly from shadow to light on the curved surface of the hull.

This could be a Cycles issue; I'd be interested in seeing an example of this. Cycles doesn't always (but sometimes! very inconsistent) deal well with approximate curved surfaces with a relatively low polycount. Sometimes, it won't show a smooth gradation of dark-to-light and will instead decide that one polygon is in full light while the next adjacent polygon is full-dark, giving rise to jagged, almost cartoonish shadowing. This can usually be fixed by increasing the polygon density in the problem area.

My lighting setup is a sun, and a single fill spotlight (very faint settings in Blender render - just light enough that my shadows aren't pure black) almost exactly opposite my sun, both vertically and horizontally.

Sounds good! That's basically what I use nowadays. I started out with more convoluted light setups, but now I just go with a Sun and a "Planet" (blueish fill) light and call it a day. I generally do both as Suns, though, rather than using a Spot for one. And I keep them both "targeted" at an Empty node in the center of the scene with a "Track To" constraint. If you're unfamiliar with this and want to know more, just let me know!

If you could explain this to me in a way that I can understand, it would be appreciated. Treat me as if I'm a complete newbie to the software - please don't make the mistake of a lot of tutorials I've seen where they assume you already know something about what you want to do. I don't (at least, in regards to Cycles), and also I have a slight learning disability that makes it difficult for me to follow written directions, unless they are explicitly written out. OTOH, I *have* figured out where you get those fancy node images that I always see you posting, so if you say, "Go to the Node Editor," I've got that.

Let me know if the above is too glossed-over to follow and I'll be happy to write it out in more detail!

I also don't get a transparent background, even though I have PNG and RGBA selected:

PNG/RGBA only gets you so far. Need to make sure a couple of things are in place, but the most important one is to make sure that under the "Render" tab of the Properties editor, under the "Film" rollout, that "Transparent" is checked. If it's not, your background will always be considered opaque by Cycles.



Feel free to hit me back with any other questions!

MaxxRush

Okay... the background transparency problem is solved easily enough. Thanks for that.

I also tried setting up the node editor exactly as yours was in the image you posted, but the render still came out dark, no matter how much I played with the output of the sun, increased or decreased the AO, or tried anything else you mentioned. I suspect I'm missing something somewhere. I was able to get cast shadows to appear, but again, they weren't very dark, and the light areas weren't very light. OTOH, I wasn't able to reproduce the sharp shadow transition on the curved hull (the entire mesh is a little over 250k polys - the hull itself is a bit over 55k).

Anyway, that's where I stand right now. I had a little trouble figuring out where you got those nodes labeled "add" and "Multiply", but I finally figured it out. It's not really all that important that I get this going right away, but I just figured it would be nice to have renders done in a couple minutes, as opposed to the 15-20-30 minutes I get with some of my other ships where the poly count is 2+ million, and the light count can go over 200, depending on the size of the boat bay(s) and number of personnel and cargo docking tubes.

McC

MaxxRush wrote: »

Okay... the background transparency problem is solved easily enough. Thanks for that.

Glad to hear it!

I also tried setting up the node editor exactly as yours was in the image you posted, but the render still came out dark, no matter how much I played with the output of the sun, increased or decreased the AO, or tried anything else you mentioned.

Came out dark, hm? Can you post an example? A sun lamp shouldn't need to be overdriven to be visible. I usually set mine to ~1.5 or so. When you use object illuminators, sometimes you have to crank the Emission value up way high (as in several million!), but lamps generally don't have that problem.

A few random thoughts:

• What color space are you rendering in? Properties panel > Scene tab > Color Management rollout. I generally render in "Raw" with Exposure and Gamma set to 1 and 1.8, respectively, and a special Curve setting to get the look I like, but this pressuposes you're working in a Linear Workflow. Most hobbyists don't; "Default" is generally preferred for that sort of stuff. Linear/Raw does look darker by default and needs Gamma to compensate when displayed on your monitor, if that's what you're rendering.
• It's vaaaaguely possible your Bounces aren't set high enough (Properties > Render > Light Paths), but I kind of doubt it.
• Make sure your Exposure isn't turned way down (Properties > Render > Film > Exposure); manipulating Exposure is definitely something one might do with a Linear workflow, but isn't usually necessary in sRGB (default monitor color space)

If all else fails and you're comfortable doing so, I'd be happy to take a look at your .blend file and see if I can diagnose it.

MaxxRush

McC wrote: »

If all else fails and you're comfortable doing so, I'd be happy to take a look at your .blend file and see if I can diagnose it.

Give me a couple days and I can send you one. Probably not this one that I used earlier, though. Reason being is that it's not "officially" released. However, the file I end up sending will be very similar to it, but just of a bigger ship, with a lot more polys and stuff. The reason I need a couple days is because this particular file (the one I posted renders from earlier) has several things that are also in the other files changed, and I want to update the old ships with the new stuff to give you as much info and things to analyze as possible.

Just a quick question, but is it possible to save a particular Cycles render setup and reuse it from one mesh to the next? I'm assuming it is, but I don't want to find out the hard way that I'm wrong.

In the meantime, I'll also try out some of the suggestions you made.

Last thing for now - I really appreciate the time you take from your own modeling to answer questions and help people out like this. It's a godsend to those of us that can't figure things out on their own and those like me who have problems learning new things.

McC

MaxxRush wrote: »

Give me a couple days and I can send you one. Probably not this one that I used earlier, though. Reason being is that it's not "officially" released. However, the file I end up sending will be very similar to it, but just of a bigger ship, with a lot more polys and stuff. The reason I need a couple days is because this particular file (the one I posted renders from earlier) has several things that are also in the other files changed, and I want to update the old ships with the new stuff to give you as much info and things to analyze as possible.

Sounds good! No rush here.

Just a quick question, but is it possible to save a particular Cycles render setup and reuse it from one mesh to the next? I'm assuming it is, but I don't want to find out the hard way that I'm wrong.

Kind of. At least, so far as I know. Basically, if you save some settings in the "blank" scene Blender loads up when it first launches, those settings will stick across any new files you make. However, individual scenes all keep their own render settings, so there isn't really a way to "copy" the settings from one scene to the next without making them part of the default startup file.

(If someone out there wants to correct me on this, I'd be delighted to hear it!)

Last thing for now - I really appreciate the time you take from your own modeling to answer questions and help people out like this. It's a godsend to those of us that can't figure things out on their own and those like me who have problems learning new things.

Glad to!

I was telling my wife earlier that very few things make me as happy and satisfied as being able to help other people with this stuff. Maybe that makes me weird, but I really enjoy sharing knowledge and helping other people solve problems with 3D stuff and with Blender in particular. I don't really know where it comes from, but any time I can help just one person get a little bit further in Blender, I'm really happy about it!

That said, I should probably spend some time modeling :rolleyes: Haven't done very much lately. Being playing too much STO...

MaxxRush

McC wrote: »

Sounds good! No rush here.

Part of the reason for the delay is a Non-Disclosure Agreement I'm under. I *can* release images, as I've done before, but an entire file...? I need to get with someone on that to allow me to release a file to you. I don't think there would be any problems getting permission though, and you've been around here long enough that I feel I can trust you not to send the file into the cloud (or wherever).

McC wrote: »

Kind of. At least, so far as I know. Basically, if you save some settings in the "blank" scene Blender loads up when it first launches, those settings will stick across any new files you make. However, individual scenes all keep their own render settings, so there isn't really a way to "copy" the settings from one scene to the next without making them part of the default startup file.

(If someone out there wants to correct me on this, I'd be delighted to hear it!)

I figured it would be that way, and that's perfectly fine, as that's what I do with my lighting, camera, and rendering (Blender render) setup - they're part of the startup file, and I was hoping I could do the same with a Cycles setup, since all my current renders use the same lighting. That way, if I can get this figured out, I can get renders done much quicker.

The flyby video in my sig took two full months - to the day - of 24/7 rendering to complete. That was before my comp upgrade (had an AMD quadcore, AMD HD7970, and 8GB of DDR3 1600), and using the default rendering engine. If I can cut rendering times down as much as it seems I'll be able to taking advantage of the CUDA set in my 780Ti, I might be able to do more animations.

McC wrote: »

Glad to!

I was telling my wife earlier that very few things make me as happy and satisfied as being able to help other people with this stuff. Maybe that makes me weird, but I really enjoy sharing knowledge and helping other people solve problems with 3D stuff and with Blender in particular. I don't really know where it comes from, but any time I can help just one person get a little bit further in Blender, I'm really happy about it!

That said, I should probably spend some time modeling :rolleyes: Haven't done very much lately. Being playing too much STO...

Funny you should mention STO - one of the other guys I work with in BuNine is Thomas Marrone, who does design and interface work for STO as his day job. Here's his deviantArt: http://thomasthecat.deviantart.com/

I don't play it myself. I'm looking forward to Dragon Age: Inquisition, though. In which case, I may take a break from Honorverse modeling.

Maybe.:D

Polaris 004

Thanks for this thread Tralfaz. I have a Blender question that is driving me nuts.

Last year I learned a neat trick, and now I can't remember where I saw it or how to do it. It was a tutorial on this site, I think, but I just have not been able to find it. Basically, It let you select a path of vertices, and then select a curve or a circle, and it would stretch that shape over the trail of vertices. It was a great way to make pipes or tubes over the surface of a hull. It was easy and gave great results, but I can't remember exactly how it was done. I need this trick to finish the detail on my Galaxy Class Stardrive Battle bridge area. Can anyone help?

McC

Is it this?

Unfortunately, I'm not sure if that script works anymore. Last time I tried it, I got all sorts of errors. I poked at debugging it a bit, but didn't want to spend too much time on it at the time.

Polaris 004

McC wrote: »

Is it this?

Unfortunately, I'm not sure if that script works anymore. Last time I tried it, I got all sorts of errors. I poked at debugging it a bit, but didn't want to spend too much time on it at the time.

Yes! That was it. I will be sure to archive it properly this time! Thanks!

I have a second computer with the pre 2.7 Blender install on it. I will just export a file to work on the piping over there, then shuffle it back and integrate the piping work back into the main file. That should work, right?