Printable View
I found this once now I can't remember how I did it. I'm trying to create a vase from a profile shape I created in Xara. I have my shape converted to a mesh and I know I need to extrude and spin the shape to create my vase model. I just can't remember how to spin the extrusion. And I am going to tackle creating or (at least attempting to) glass, so any tips for doing that would be really helpful.
Thanks in advance!
Hello Frances,
When you go to spin something, just remember that it defaults to spinning around the view axis. In other words, if you're spinning a vase, you make the profile from the front view, but spin it from above.
Just highlight your path in edit mode and then on the left toolbar, use Spin. It defaults to 9 steps and 90°, so just make it 360° of course and as many steps as you need to get the effect you want. You may also want to use less steps and use a SubSurf modifier as per my other recent post. (and the way I did it on my vases that I posted in Larry's scribble thread)
Hope this helps...
In the event that you have problems spinning the converted curve (sometimes spin is a bit iffy about having the correct path drawn), then you can just make a new object and follow the contour of the one that you imported.
Peace
James
Thank you, I knew I'd found it somewhere, and my vase spun perfectly. I'm calling it a night for now but hopefully tomorrow I'll try to make it look like clear glass. Any tips for that?
Hello France,
You are welcome!
Re: Clear glass
There are many varieties of glass. The first question is if the vase refracts light or not. If so, then you'll (likely) have to play with the Index of Refraction to get it warping the light correctly. Though it might not be intuitive, the Index of Refraction drastically changes as small changes are made. You're basically telling it how much to warp the light and you can see that as you warp it more and more, those rays of bounced light end up in quite different places depending on this IOR. Small amounts are more like pane glass, while higher values can simulate almost any transparent or semi-transparent materials.
So...first, (after selecting the vase) turn on Transparency and select RayTrace (you can have glass without raytracing, but you can't have refraction without it). The Alpha value needs to be set to a very, very low value (otherwise the diffuse coloring of the glass is too prominent).
There are some other settings that you can play with, esp. the Fresnel value...but in general, the above is what is necessary to making realistic glass.
Hope this helps... one other little advice. Most glass not only refracts light, but also (on some small level!) reflects light. Because of this, your eyes expect to see some reflection of the environment. I would use it very sparingly (the reflection), but would include it. You can also use the Gloss amount (as per my other post about mirroring) so as to not have the reflections be so perfect that they're distracting.
Let me know how it comes along... I'm happy to help you find the perfect glass for your vase. :)
James
thanks for this. It may be a while before i get a chance to play with this, but I'm looking forward to it! I'll be sure to post my results
Hello Frances,
I didn't like any reflection on this one, so went with only the specular highlights.
I made these to show how Index of Refraction alters the "glass vs crystal" element of the vase.
Attachment 84208
Hope they help
James
The Index of Refraction for some typical materials:
http://hyperphysics.phy-astr.gsu.edu...les/indrf.html
This link may be more usable by 3D modelers though ;) : http://www.robinwood.com/Catalog/Tec...IndexList.html
That's really cool James.
I'm sure that list will come in handy when I get more into this.
Now another question: My vase has a seam from spinning it and I can't get rid of it. It didn't show up until I started smoothing the vase and recalculating doesn't get rid of it the ctrl+2 lessened it but not much how do I get rid of the seam?
James can probably tell you right off the top of his head. I seem to remember something about removing duplicates immediately after making the spin.
CTRL-V to bring up the vertex menu and Remove Doubles to remove the overlapping vertices.
I just tried that and it helped but there is still a seam, perhaps because I spun the vase last night but saved it and decided to work on it some more tonight? perhaps the only the end vertices should be selected?
Hello Frances,
What I normally do is, right after spinning, while still looking from the top, I select "B" (box select) and draw a rectangle around the vertices that are selected. This also causes the doubled vertices (the reason for your seam) to be selected. Then, (just as Bill said) use Remove Doubles and the seam should be gone. Remember that if your object has weird shading that it means that some of the normals are pointing in the wrong direction. In that case, just select all faces and hit "Recalculate".
Note: Remember that when you are doing the box select that you don't just want the vertices that you can see, you have to get all the vertices down through the object, so make sure that "Limit Selection to Visible" is turned OFF.
Attachment 84212
(Shown in the ON position, but you want it OFF)
You could also just Select All and that will work fine for the Remove Doubles, in this case. My workflow is to box select them, just so I know that only those along that seam will get eliminated. (in case in some model there are very close nodes, but that I don't want to become poles (vertex with too many edges flowing from it, messy geometry)).
James
Re: Index of Refraction
Since the Index of Refraction makes quite a difference visually (by its effect), I tend to set something close to clear glass and then add more until it looks the way that I want.
Originally, I did pull up the list and would use the list for things other than normal glass. The 1.1 to 1.5 area works pretty well for glass without making too many dull spots. (The dull spots occur when there is a too high (for the image, anyways) Index of Refraction and the glass is warping light in what seems like an unnatural way. You can see a hint of that at the higher values in that simple Index of Refraction anim that I made for your reference.
Like many things in Blender, this is another case where a little bit is good, but a whole lot is not better. ;)
James
Well here is my vase I am quite pleased with it. Thank you James and Bill for all your help. One thing I noticed, I put a couple of objects in my scene (but didn't render them) and set reflections on, boy that increases render time!
Attachment 84214
Nice one, Frances ! You're way ahead of the other students !
Hello Frances,
Very cool vase. It's definitely glass! :) I see you got the seam, etc., problems worked out.
And... now that you've created it, you can view it from any angle, any lighting, etc., and without having to redraw a thing. ;)
I know you...there's bound to end up being some flowers in that vase!
Great job!
James
Re: Render Time
Yes...any refractions/reflections adds a lot to the render time, since it must bounce rays (equal in number to the sampling) for each pixel that hits a refracting or reflecting object and then trace it on through to its destination. Still though, depending on computer resources of course, I think it's quite fast.
It seems like a long rendering time, perhaps, but I can still remember back around 1987 [using Imagine (originally TurboSilver) and Sculpt-3D (later Sculpt-4D)], when doing this kind of stuff. For even simple scenes (if there were a lot of mirroring or glass) I would start a render in the morning...go about my day and hope it was done when I got home in the evening. Oftentimes it wasn't. Thank goodness the Amiga was a very well-architectured multi-tasking computer.
Back then, it was all scenes...no anims. One could do anims, but I didn't have the computer time to dedicate for all those rendered frames. Now, with today's computers (and software like Blender, ie. more efficient) I can have high-resolution, mirrors and glass, and can still animate without it taking all day.
Peace
James
Yes I was thinking about flowers ;)) I actually have and idea but I'm not sure if I'll be able to pull it off yet. As for render times: An all day render good grief! I thought 4 or 5 mins was long!
Great looking vase Frances.
Render times have definately improved over the past 20 years. I recall some renders taking 103+ hours. :-O
Re: Rendering Times (then vs. now)
Not the least of which is computer speed. From MHz to GHz! Multi-cores. The images are much better (more color, better anti-aliasing in general) and take much less time to do. The editing tools are really powerful. If I'd had Blender (as it is now) then, I would have ruled the world. ;)
I'm glad, after these many years to come back to these types of tools. Anything you have the ability and take the time to make, you can see in pretty much any way and can manipulate it and even animate it. And yet, it all still feels like playing.
Bill, I would not have had the patience to let it cook for 103+ hours.
James
James it wasn't so much having patience but planning. Start the render then take a few days Holiday. ;)
Re: Holiday
How many renders a year is that? ;)
You did make me think of an important point about Blender since we were discussing rendering times. While setting up the scene and doing test renders, it is a good idea to change the image size under Render tab. It is specifically set up to allow percentages, so you don't have to mess with dimensional numbers. Set your end render image resolution to whatever you want. Then, when doing test renders, decrease the percentage slider so that you get relatively quick feedback.
If you set the slider to 67%, that's in both horizontal and vertical, so 2/3 * 2/3, which is 4/9, which means you get 2/3 the finished image size, but less than half the time to render it. Set it at 50% and it has 1/4th as many pixels to render. 33% image size takes 11% time-wise.
This usually only becomes pertinent if there are significant refracting or reflecting surfaces... (or some of the more advanced features like simulating hair, etc.)
James
That's a great tip James, thanks. I have an idea for something I'm going to try later, if I can make it work I'll have that vase filled ;)
One for Bill...
Attachment 84236
That's cool, did those begin in Xara?
Hello Frances,
Yes, that did start in Xara. I drew the batman logo and then SVG imported it into Blender. It wasn't quite as smooth as I wanted it upon importing. When I imported, applied SubSurf modifier and then the Array to make the copies, it was 2,100,000 faces! That many faces makes Blender move a bit slower. ;) It also increased the rendering time, of course. This one took 17 minutes and is one of the longer renders. Since first working on this one, I've learned how to do similarly but lower-poly.
Glad you liked it...
James
I've noticed that when you convert a curve imported as a svg from Xara to a mesh you sometimes get a lot of faces is there a way to simplify these meshes?
Hello Frances
There are several ways to simplify the meshes.
One approach is to manually go in and make more logical faces. Look also into the Beautify Fill function. ( <- under Faces) You can even go back and get rid of the faces and many of the vertices and then refill the object using more logical/structured face-creation.
Another approach is to load the object (or an image, actually) and just trace the object to create from scratch. Smooth objects especially work with this method as the SubSurf modifier makes it look smooth like the original.
Another approach is the cloth simulator. If you drop a cloth exactly on an object, it's possible to use that cloth then as the object... it will have the geometry that was used when creating the cloth, but shaped to the object.
There are other ways, of course. To find some of them, just do a search for "Blender retopo" and you should find plenty of articles.
If an object needs to have an exact shape, then the SVG works very well. It's a little sloppy when converting to a mesh, but that can be cleaned up if necessary.
When there is a little "artistic license" possible (ie. the object doesn't have to be to an exact cut), then I would tend to bring in the shape and just recreate it manually. It's easier than it sounds... Really, only when you start getting a very high number of Vertices/Faces do you really have to worry about these resources. (enough memory for the faces you've created)
Peace
James