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Blender FBX export loPoly Bake from hiPoly model -> Import into UE4

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  • replied
    Originally posted by lo2dk View Post
    Not sure I understand this part. Do you mean I should actually have 3 objects and not just 2 (low poly + high poly) ? The 3rd object would be the control cage for bake? If so , what order should I select my 3 objects before baking?

    Blender file (updated): http://www.pasteall.org/blend/41193
    Yes the 3rd object is the cage for baking. You select the high poly and then the cage to bake. Not the low poly at all because you already UV wnwrapped your low-poly before duplicating it to make the cage it will use the same UV layout. So you're only exporting the low poly with it's material that uses the bakes from the cage.

    Really this approach is just because in some situations you might need to make adjustments to the cage that you don't want to make to the low poly, or if you have a stack of modifiers on the low poly that aren't good for a cage (e.g: Edge Split).

    Looked at your file, your UV layout really was fine before, you only really need to create UV seams on large angle changes like from the sides of the barrel to the lid.
    Last edited by Mangley; 03-23-2016, 12:13 PM.

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  • replied
    Originally posted by Mangley View Post
    To do a really nice bake in Blender you should then duplicate the UV unwrapped low poly, remove the Edge Split modifier from it and add the Displace modifier (This is the equivalent of the Push modifier in 3DS Max), change the value so it expands and covers the model closely andthen bake the same way you did before. Ultimately the closer the forms of the low poly are to the high poly the better the result is going to be.
    Not sure I understand this part. Do you mean I should actually have 3 objects and not just 2 (low poly + high poly) ? The 3rd object would be the control cage for bake? If so , what order should I select my 3 objects before baking?

    Blender file (updated): http://www.pasteall.org/blend/41193
    Last edited by lo2dk; 03-23-2016, 10:38 AM.

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  • replied
    Originally posted by lo2dk View Post
    Thanks. Will do.
    Do I need to UV unwrap both the high poly model as well as the low poly model? I thought it was enough to unwrap the low poly model.
    Only the low poly needs to be UV unwrapped.

    I'm a Blender person, I took a look at your file and I have a bunch of advice:

    I recommend building the low poly from the high poly by duplicating it, removing the subdivision modifier, and dissolving edge loops not needed in the low poly (select them, Delete > Dissolve Edges) Then you should add smoothing groups to your low poly by applying smooth shading to it in object mode then selecting edges that should be sharp and doing Ctrl + E > Mark Sharp. Then apply the Edge Split modifier to your low poly. Then you can set the UV seams the same way by doing Ctrl + E > Mark Seam and then UV unwrap the low poly.

    To do a really nice bake in Blender you should then duplicate the UV unwrapped low poly, remove the Edge Split modifier from it and add the Displace modifier (This is the equivalent of the Push modifier in 3DS Max), change the value so it expands and covers the model closely andthen bake the same way you did before. Ultimately the closer the forms of the low poly are to the high poly the better the result is going to be.

    As for your low poly itself I recommend adding a bottom to your barrel so it can be used on it's side or placed on a transparent floor such as a metal grate in environments.
    Last edited by Mangley; 03-22-2016, 06:52 PM.

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  • replied
    Originally posted by Mac_Orion View Post
    you need to set the shading of the lowpoly to smooth. Baking with flat shading doesn't work.
    Thanks. Will do.
    [MENTION=94020]AnyOne[/MENTION] : Do I need to UV unwrap both the high poly model as well as the low poly model? I thought it was enough to unwrap the low poly model.

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  • replied
    you need to set the shading of the lowpoly to smooth. Baking with flat shading doesn't work.

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  • replied
    Originally posted by Sigmafie View Post
    (1) In UE4 you have not created a new material and applied it to the barrel. You will need to create a new material, import your normal map (do not worry about AO), paste the normal into the barrel's material graph and connect the normal to the normal input of the material output node (the big one). Also, go ahead and make a diffuse color (a simple 3vector) with a greyish color, and hook that into the diffuse color slot of the material output node. Save the material. Apply the material to the barrel. This will allow you to see the effects of the normal map being applied to the game mesh in-engine.
    Thanks for your reply. I tried to improve upon the low poly model, I realised I had a seam on the top end that I shouldn't have. So the UV map is now better which also resulted in better Normal map.

    I still don't know what you mean by making a new material in UE. I will have to try and look up on some material tutorials in UE. It saddens me it needs to be this difficult. I mean the legwork was already done in Blender (UV mapped and baked and exported to FBX). This seems like a lot of double work for no reason.

    Here are the new low poly model (removed the extrutions as you suggested) and the new normal map:

    Click image for larger version

Name:	lowPoly_berrel2.PNG
Views:	1
Size:	19.8 KB
ID:	345107 Click image for larger version

Name:	lowPoly_berrel_nor_2.PNG
Views:	1
Size:	380.6 KB
ID:	345108

    Still seemes like im having some of the faces cut off. Like the objects wont fit in the UV layout even though the unwrapped model, was within the boundaries of the diffuse texture to begin with.

    Blender file (updated): http://www.pasteall.org/blend/41176
    FBX (updated)http://s000.tinyupload.com/index.php...42941520821415:
    Last edited by lo2dk; 03-22-2016, 03:35 PM. Reason: forgot to add the updated blender and fbx file

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  • replied
    I do not personally use blender lo2dk, but what I will say is applicable across all the 3D packages. Also, I struggle a lot with baking normal maps just simply because it is a difficult thing to do.

    (1) In UE4 you have not created a new material and applied it to the barrel. You will need to create a new material, import your normal map (do not worry about AO), paste the normal into the barrel's material graph and connect the normal to the normal input of the material output node (the big one). Also, go ahead and make a diffuse color (a simple 3vector) with a greyish color, and hook that into the diffuse color slot of the material output node. Save the material. Apply the material to the barrel. This will allow you to see the effects of the normal map being applied to the game mesh in-engine.

    (2) Baking is difficult. Baking cylinders is even more difficult (take a look at my roman column bake and you will see issues as an example). You will want to smooth your low-poly-or soften edges as in the case of Maya-(prior to the baking) so that the normals (the ray projections to calculate the normal map) are averaged across those areas you want it averaged. Your current normal does not appear to reflect a smoothed low-poly asset. You may bake in most 3D package or xNormal or Substance Designer (I don't remember if Marmoset Toolbag bakes). Take a look at http://wiki.polycount.com/wiki/Normal_map for more information on normals. Note that seams are unavoidable. xNormal is a good, free, alternative if you do not have access to other programs and it will produce an OK cage if you choose to do a caged bake (which you should).

    (3) It looks like you have a chunk missing from your UV map, and your bakes will be incomplete.

    (4) Your low poly has some areas of detail that are unnecessary and look like they will complicate the normal map calculation, resulting in waviness (which I can see some in the normal map on the top portion of the barrel). The low-poly really only needs to match the silhouette of the high-poly. I suggest eliminating the interior extruded ring, and instead extrude the opened border smaller, than upwards, and finally close the mesh. Move the smaller ring to the location of the "cap" that is present on the mesh.

    (5) Your high-poly looks good, although it may be too soft (chamfers may be too wide) on the sides, but I would test-bake first and see how it looks in-game.

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  • Blender FBX export loPoly Bake from hiPoly model -> Import into UE4

    Hi.

    As stopic states I need help , mostly general how I get around a hiPoly model im happy with, and then saving that extra detail into a lower poly model for UT4.

    I tried something really basic first, make a high poly model of a berrel vs a low poly berrel and bake AO+NOR:

    Click image for larger version

Name:	hiPoly_berrel.PNG
Views:	1
Size:	215.4 KB
ID:	361809 vs Click image for larger version

Name:	lowPoly_berrel.PNG
Views:	1
Size:	57.4 KB
ID:	361810 , AO: Click image for larger version

Name:	lowPoly_berrel_ao.PNG
Views:	1
Size:	357.4 KB
ID:	361811 , NOR: Click image for larger version

Name:	lowPoly_berrel_nor.PNG
Views:	1
Size:	421.6 KB
ID:	361812

    1: I realise the low poly model is not smoothed is this a problem?
    2: In my low poly model , Do I need the extra extrusions around the higher and lower part of the berrel sides - in order for the bake to reach the details in the high poly image ?
    3: What can I do so that UT4 editor use the details from the baked maps? Heres how silly it looks in UT4 editor when I import the .FBX :
    Click image for larger version

Name:	ut4_fbx_import.PNG
Views:	1
Size:	849.3 KB
ID:	361813 , clearly it isn't using the baked maps.

    I hope you can help me somehow because I need to grasp these basics before I can contribute with making pretty static mesh assets for UT4 maps. :-)
    Blender file: http://www.pasteall.org/blend/41171
    FBX file: http://s000.tinyupload.com/index.php...42754977646491
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