crappy renders?

hi! i recently started a project with blender and was doing some test renders. i noticed that in most places on the rendered mesh where it should have been flat it looked a little bumpy. i turned osa up all the way and it dampened it a little, but the bumps are still noticable. like on this hydraulic shaft it is totaly straight, but when i render it , it appears to have 2 very small bumps going up it. i tried a lot of stuff, looked through the guidebook, but still no luck!(i even redid a lot of components to add more polies) anyone know what is causing this? from what i can tell its just the way it renders, but i never noticed it until now.

sorry if its not very clear what i am trying to say, i would provide a pic, but i dont have internet at home yet. if you really need one i can put it up tomorrow.

I have no idea what the problem may be, I think you’ll need to post a screenshot.

On the other hand, it might be because you have subsurf turned on, and you haven’t increased the subsurf value for the render.

If you look at the subsurf panel you’ll see two numbers under the subsurf button that say “Subdiv 1 | 1” as defualt. If you’re using subsurf then you need to increase the second value as well as the first one. The first one only affects what you see in the 3D window.

Select the offending object, Tab into edit mode, A or AA to select all verts and use Ctrl-N to point all Normals outside.


ill try that fligh %, if it doesnt work (sure it will :smiley: ) ill post a shot tomorrow. and hopefully get a wip up in the wip forum. btw: im not using subsurf objects, thanks

heres what im talking about:

and this is after i antialiased it at 16 overesamples :-? (pic enlarged in microsoft paint once using magnifying tool)

That image really doesn’t help at all, why did you have to magnify it?

egh… i enlarged it to show you the crappiness in more detail. cant you see how rough the edges are? it shouldn’t look like that, it should look smooth. unless it just renders like that . that thumbnail is about the same size as the portion i cut out of the full sized render.

What is the render size? In many cases I will render my images at double size then scale them down in Photoshop. Makes for a much sharper image.

try clicking on unified renderer, maybe that will work.

Are you using the RENDER button in F10 (alternate is hitting F12)?


yes i am hitting the f12 button to render it. the imagesize is like 1200 x 900 or somewhere abouts there. unified renderer? ill try that i guess… i tried rendering this in yafray also, but the same results. it seems as though the renders should take longer than they do, but maybe not considering the shadows im using.

To me it looks like the rendered image doesn’t fit on screen, so blender rescales it (And you took a screenshot? …). Render at 640*480 and see if the problem is still there.

I’m not sure there is a problem. When you zoom into a digitally made picture, you reach the point as you have done where you see blocks. If you need to be able to zoom in that close without seeing blocks, you need to render at a higher resolution.

You will see artifacts if you zoom into any rendered picture. This might be confusing if you have zoomed into pictures from digital cameras or scanned images and not seen blocks. The reason they don’t show the blocks so much is they are normally higher resolution.

Here I have zoomed into a digital photograph:

is there a way to set the resolution in blender? if there is im sure ill find it in the guide book at home… thanks! and i tried rendering it at a smaller size before, but the same results appeared. :-?

are yuo sure that you have osa on?
you have to click the top button and one of the lower buttons to turn it on.

yes 100 percent sure i have the button clicked…but sometimes it is the most obvious things that undermine you :smiley: . could it possibly be a hardware issue at all? i have pretty good specs and meet alla the requirements…but still… :-?

How are you saving the render? Nico has already asked if you pressed the PrintScreen key. If you took a screenshot and then pasted into Microsoft Paint, which seems to be what you are using, then I most certainly see why it’s doing that if the render is larger than your screen size or if you have the display render in viewport button on.

For rendering a still you should always save it by pressing F3 after it’s done rendering. The file type is specified on the right-most panel in the scene buttons. Make sure you add the extension when you save it and then it should look fine.

And if you are using Paint, for goodness sakes get The Gimp for Windows.

Why did you render at a smaller size? That makes the problem worse. In the sizeX and Y boxes, you set the resolution you want the image to be used at. You can render as high as 10000x10000 or so.

Make sure you have the button labelled 100% clicked too and not 50% (which I think is the default for some reason). 50% means that if you intend to use an image at a certain resolution, it will render at half and when you zoom it up, you will see blocks.

Other things to make sure is that you use PNG compression or some other lossless codec. It could be that you are using JPG with a low quality. If you don’t know how to save image, once a render is finished, go to the file menu and do “save image”.

I agree with some of the previous posts. Blender will resize the render window to fit your screen if it is smaller than the image you are rendering.

This resize algorithm is quite simple, but for preview purposes only.

Does the jagginess occur on the image file you are rendering to, or just the Blender rendering window you are looking at?

Make sure you’ve got a filename and image type set in the rendering options, render the image and have a look at the image file that is created, not the rendering window.

also in F10 under render it has four buttons each saying 100%, 75% etc make sure you have the 100% button pressed for it to come out full size
i’ve made that mistake a couple of times