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Game Editing => 3D Modeling & Content Creation => Topic started by: JanXuan on June 21, 2017, 05:35:05 AM

Title: Add drawing to grid
Post by: JanXuan on June 21, 2017, 05:35:05 AM
Is it possible to add a jpg 3D view drawing to the grid to help as a guide for a project?
So I am not talking about a Blender drawing.
Or, for that matter, is it possible to extract objects from such a drawing?
Title: Re: Add drawing to grid
Post by: JanXuan on June 21, 2017, 12:49:00 PM
I thought that I had a solution for this. I used the drawing as material and stretched the cube to the grid, then I made a plane which I went to shape into a wing, however to find out that the plane had become a face on the cube, which I could not move independently.  ;D ;D ;D

Never mind, I figured it out.
Title: Re: Add drawing to grid
Post by: kat on June 21, 2017, 07:38:12 PM
To answer your original question, yes they can be added using "Background Images (https://www.katsbits.com/tutorials/blender/sword-make-low-poly-sword.php#background)". They need to be jpg, png, tiff or other recognised format. Basically, press "N" to access the "3D View Properties" panel. Scroll down to the bottom and activate "Background Images". Browse to and select the image you want, then load. Only works in Orthographic views though, not 3D perspective.

(https://www.katsbits.com/images/tutorials/blender-make-simple-sword/blender-sword-view-properties-background-image.jpg)
Title: Re: Add drawing to grid
Post by: JanXuan on June 21, 2017, 08:05:56 PM
Thanks. That did not help me much though.:)
I'll have to work it out with my own solution.  ;D ;D ;D
Title: Re: Add drawing to grid
Post by: kat on June 21, 2017, 08:49:45 PM
That's actually the other way to do it, UV map the image onto a flat surface. To make sure it works correctly the surface needs to measure the same size as the image, e.g., a 1024x768 pixel image should be mapped to a 1024x768 UNIT surface (or 10.24x7.68 etc.).
Title: Re: Add drawing to grid
Post by: JanXuan on June 21, 2017, 09:27:35 PM
After setting the image as texture, take a block that you don't need, flatten it as much as possible, and stretch it to the grid or to the size that suits you best. Make sure that the image has equal sides. Save the file as start file for this project so you can make seperate objects that you can join later. When the project is done, delete the background block.
Title: Re: Add drawing to grid
Post by: kat on June 21, 2017, 10:14:52 PM
After setting the image as texture, take a block that you don't need, flatten it as much as possible, and stretch it to the grid or to the size that suits you best. Make sure that the image has equal sides. Save the file as start file for this project so you can make seperate objects that you can join later. When the project is done, delete the background block.
If the end result, the model being made, needs to match the reference image exactly, don't do this because its producing an arbitrary relationship between reference image and reference surface. All that's needed is a plain (or other flat surface per orientations needed) that's the exact same dimensions as the image - this avoids X or Y axis distortion by trying to fit the image to a incorrectly sized surface.

In "View" Properties, "N" (or "Object" Properties), change the "Dimensions" values of the object to reflect the reference image - as per the above for a 1024x768 pixel image this can be 1024x768, 102.4x76.8, 10.24x7.68 or 1.024x0.768 (the ratio is important in relation to the surface size, so long as a derivative of the original measurement is used a 1:1 match is acquired). Use "Apply", "Ctrl+A",  to reset the mesh once done. Then remap the UV to an image that matches the reference (if a single image is being used for multiple orientations, make each plain/surface the same size and then shift the UV map relative to the image rather than cutting or manipulating the mesh object, this avoids distortions).

If the original image is an arbitrary size, alter its background size in an image editor so it fits within the realms of the "power-of-two rule (https://www.katsbits.com/tutorials/textures/make-better-textures-correct-size-and-power-of-two.php)" - alter the image back ground, not the image itself, this avoids distorting the object information that's to be used as a reference.
Title: Re: Add drawing to grid
Post by: JanXuan on June 22, 2017, 12:27:25 AM
If the cube has equal sides and the image has equal sides, so both are squares, it can still go wrong?
Title: Re: Add drawing to grid
Post by: kat on June 22, 2017, 12:51:05 AM
It's a common mistake, resizing the reference image in Photoshop so its easier to fit to a cube. Doing so results in a distorted model. Basically always match the mesh/surface to the reference image, rather than image to mesh/surface. If the image has to be adjusted make sure to only alter the 'background' instead of the main body in photoshop et al (the layer the 'object' being replicated in 3D sits on).
Title: Re: Add drawing to grid
Post by: JanXuan on June 22, 2017, 03:50:22 AM
Well, I don't know what I am doing wrong, because when I try to do it your way, the image is devided over 6 sides of the cube, and changing the size does not change the image.
I feel like the model looks perfectly good to me, so if you don't mind I continue my way, as your suggestion does not work for me.
Title: Re: Add drawing to grid
Post by: kat on June 22, 2017, 04:15:50 AM
No problem.

To address the issue presented though, when using a cube just delete the unwanted sides, the image can then be manipulated appropriately to fit each orientation. For example if a single image holds the main cardinal orientations of top, front, left/right, UV map each face of the cube to the image and adjust the alignment in the UV/Image Editor (don't alter the cube). When doing this however, make sure to scale UV's as a unit, select them all then manipulate, otherwise they'll end up being different sizes and your views won't match.